256621533273641 has 4 divisors (see below), whose sum is σ = 256654865082000. Its totient is φ = 256588201465284.

The previous prime is 256621533273631. The next prime is 256621533273709. The reversal of 256621533273641 is 146372335126652.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 256621533273641 - 2¹⁸ = 256621533011497 is a prime.

It is a super-2 number, since 2×256621533273641² (a number of 30 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (256621533273631) 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, 16665892631 + ... + 16665908028.

It is an arithmetic number, because the mean of its divisors is an integer number (64163716270500).

Almost surely, 2^{256621533273641} is an apocalyptic number.

It is an amenable number.

256621533273641 is a deficient number, since it is larger than the sum of its proper divisors (33331808359).

256621533273641 is an equidigital number, since it uses as much as digits as its factorization.

256621533273641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33331808358.

The product of its digits is 32659200, while the sum is 56.

The spelling of 256621533273641 in words is "two hundred fifty-six trillion, six hundred twenty-one billion, five hundred thirty-three million, two hundred seventy-three thousand, six hundred forty-one".