1215267761 has 2 divisors, whose sum is σ = 1215267762. Its totient is φ = 1215267760.

The previous prime is 1215267751. The next prime is 1215267769. The reversal of 1215267761 is 1677625121.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 804800161 + 410467600 = 28369^2 + 20260^2 .

It is a cyclic number.

It is not a de Polignac number, because 1215267761 - 2¹⁴ = 1215251377 is a prime.

It is not a weakly prime, because it can be changed into another prime (1215267769) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 607633880 + 607633881.

It is an arithmetic number, because the mean of its divisors is an integer number (607633881).

Almost surely, 2^1215267761 is an apocalyptic number.

It is an amenable number.

1215267761 is a deficient number, since it is larger than the sum of its proper divisors (1).

1215267761 is an equidigital number, since it uses as much as digits as its factorization.

1215267761 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 35280, while the sum is 38.

The square root of 1215267761 is about 34860.6907705513. The cubic root of 1215267761 is about 1067.1463721992.

The spelling of 1215267761 in words is "one billion, two hundred fifteen million, two hundred sixty-seven thousand, seven hundred sixty-one".