256456137621 has 8 divisors (see below), whose sum is σ = 341945455360. Its totient is φ = 170968789152.

The previous prime is 256456137599. The next prime is 256456137643. The reversal of 256456137621 is 126731654652.

It is an interprime number because it is at equal distance from previous prime (256456137599) and next prime (256456137643).

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

It is not a de Polignac number, because 256456137621 - 2¹⁴ = 256456121237 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256456157621) 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, 155536 + ... + 732873.

It is an arithmetic number, because the mean of its divisors is an integer number (42743181920).

Almost surely, 2^256456137621 is an apocalyptic number.

It is an amenable number.

256456137621 is a deficient number, since it is larger than the sum of its proper divisors (85489317739).

256456137621 is an equidigital number, since it uses as much as digits as its factorization.

256456137621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 984635.

The product of its digits is 1814400, while the sum is 48.

The spelling of 256456137621 in words is "two hundred fifty-six billion, four hundred fifty-six million, one hundred thirty-seven thousand, six hundred twenty-one".