256621007317331 has 4 divisors (see below), whose sum is σ = 257020106862792. Its totient is φ = 256221907771872.

The previous prime is 256621007317303. The next prime is 256621007317351. The reversal of 256621007317331 is 133713700126652.

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 256621007317331 - 2⁴² = 252222960806227 is a prime.

It is a super-2 number, since 2×256621007317331² (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 (256621007317351) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 199549771766 + ... + 199549773051.

It is an arithmetic number, because the mean of its divisors is an integer number (64255026715698).

Almost surely, 2^{256621007317331} is an apocalyptic number.

256621007317331 is a deficient number, since it is larger than the sum of its proper divisors (399099545461).

256621007317331 is an equidigital number, since it uses as much as digits as its factorization.

256621007317331 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 399099545460.

The product of its (nonzero) digits is 952560, while the sum is 47.

The spelling of 256621007317331 in words is "two hundred fifty-six trillion, six hundred twenty-one billion, seven million, three hundred seventeen thousand, three hundred thirty-one".