1215765131 has 4 divisors (see below), whose sum is σ = 1389445872. Its totient is φ = 1042084392.

The previous prime is 1215765127. The next prime is 1215765167. The reversal of 1215765131 is 1315675121.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1215765131 - 2² = 1215765127 is a prime.

It is a super-2 number, since 2×1215765131² = 2956169707510894322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1215765191) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 86840360 + ... + 86840373.

It is an arithmetic number, because the mean of its divisors is an integer number (347361468).

Almost surely, 2^1215765131 is an apocalyptic number.

1215765131 is a deficient number, since it is larger than the sum of its proper divisors (173680741).

1215765131 is an equidigital number, since it uses as much as digits as its factorization.

1215765131 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 173680740.

The product of its digits is 6300, while the sum is 32.

The square root of 1215765131 is about 34867.8237204446. The cubic root of 1215765131 is about 1067.2919352364.

The spelling of 1215765131 in words is "one billion, two hundred fifteen million, seven hundred sixty-five thousand, one hundred thirty-one".