I don't think so. The most #1 one singles were The Beatles with 20 #1 singles in US Billboard chart alone.
Come to think of it, with the exception of Thinking of You (and Ur so Gay, but I'm not sure if that counts as a single), every single that Katy has ever released was #1 on some chart!Thinking Of You was #1 in Brazil. Does that count?
Yes we will count that!! Dark Horse has not yet peaked, but I suspect that it will be able to reach #1 on some chart, perhaps even the Billboard Hot 100!!
This makes me wonder: is Katy the first person ever to accomplish this! Having 14 singles that were #1 on some chart (15 if you count Peacock, which was never released as a single, but was #1 on the Hot Dance Club chart). This will almost certainly rise to 15 (16 counting Peacock) if Dark Horse is #1 on any chart, which it almost certainly will.
But during that time, did the Beatles have any songs that were not #1 on any chart? Katy has not. The 15 songs I am referring to are (I won't list any other charts if a song was #1 on the Billboard Hot 100):
I Kissed a Girl: Billboard Hot 100 #1
Hot n Cold: Hot Dance Club #1 / Hot Adult 40 #1
Thinking of You: #1 in Brazil
Waking Up in Vegas: Hot Dance Club #1 / Hot Mainstream Top 40 #1
California Gurls: Billboard Hot 100 #1
Teenage Dream: Billboard Hot 100 #1
Firework: Billboard Hot 100 #1
E.T.: Billboard Hot 100 #1
Last Friday Night: Billboard Hot 100 #1
The One that Got Away: Hot Dance Club #1 / Hot Adult Pop #1 / Hot Pop #1
Peacock: Never released as a single, but Hot Dance Club #1
Part of Me: Billboard Hot 100 #1
Wide Awake: Hot Dance Club #1 / Hot Adult Top 40 #1 / Hot Mainstream Top 40 #1
Roar: Billboard Hot 100 #1
Unconditionally: Hot Dance Club #1 (has not yet peaked on the "adult" charts, so could very well be #1 on at least one of them too)
That is 15 songs, and there were no other singles released in betwen any of them. Even if you count Ur So Gay as a single, it's still 15 consecutive songs.
The likely #16 is:
Dark Horse: Has not yet peaked, but will likely be #1 on some chart, perhaps even Billboard Hot 100.