256644131613 has 8 divisors (see below), whose sum is σ = 342363023328. Its totient is φ = 171010663824.

The previous prime is 256644131567. The next prime is 256644131617. The reversal of 256644131613 is 316131446652.

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 256644131613 - 2¹² = 256644127517 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256644131617) 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, 21348970 + ... + 21360987.

It is an arithmetic number, because the mean of its divisors is an integer number (42795377916).

Almost surely, 2^256644131613 is an apocalyptic number.

It is an amenable number.

256644131613 is a deficient number, since it is larger than the sum of its proper divisors (85718891715).

256644131613 is a wasteful number, since it uses less digits than its factorization.

256644131613 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42711963.

The product of its digits is 311040, while the sum is 42.

The spelling of 256644131613 in words is "two hundred fifty-six billion, six hundred forty-four million, one hundred thirty-one thousand, six hundred thirteen".