1256265631 has 4 divisors (see below), whose sum is σ = 1259064000. Its totient is φ = 1253467264.

The previous prime is 1256265599. The next prime is 1256265641. The reversal of 1256265631 is 1365626521.

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 1256265631 - 2⁵ = 1256265599 is a prime.

It is a super-2 number, since 2×1256265631² = 3156406671263656322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1256265641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1398511 + ... + 1399408.

It is an arithmetic number, because the mean of its divisors is an integer number (314766000).

Almost surely, 2^1256265631 is an apocalyptic number.

1256265631 is a deficient number, since it is larger than the sum of its proper divisors (2798369).

1256265631 is an equidigital number, since it uses as much as digits as its factorization.

1256265631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2798368.

The product of its digits is 64800, while the sum is 37.

The square root of 1256265631 is about 35443.8377013551. The cubic root of 1256265631 is about 1079.0141984771.

The spelling of 1256265631 in words is "one billion, two hundred fifty-six million, two hundred sixty-five thousand, six hundred thirty-one".