1265856531 has 8 divisors (see below), whose sum is σ = 1688035584. Its totient is φ = 843790920.

The previous prime is 1265856521. The next prime is 1265856547. The reversal of 1265856531 is 1356585621.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1265856531 - 2¹⁵ = 1265823763 is a prime.

It is a super-2 number, since 2×1265856531² = 3204785514150707922, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1265856521) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2466 + ... + 50376.

It is an arithmetic number, because the mean of its divisors is an integer number (211004448).

Almost surely, 2^1265856531 is an apocalyptic number.

1265856531 is a deficient number, since it is larger than the sum of its proper divisors (422179053).

1265856531 is an equidigital number, since it uses as much as digits as its factorization.

1265856531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56721.

The product of its digits is 216000, while the sum is 42.

The square root of 1265856531 is about 35578.8775961244. The cubic root of 1265856531 is about 1081.7531342984.

The spelling of 1265856531 in words is "one billion, two hundred sixty-five million, eight hundred fifty-six thousand, five hundred thirty-one".