256621073 has 2 divisors, whose sum is σ = 256621074. Its totient is φ = 256621072.

The previous prime is 256620983. The next prime is 256621093. The reversal of 256621073 is 370126652.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 165456769 + 91164304 = 12863^2 + 9548^2 .

It is a cyclic number.

It is not a de Polignac number, because 256621073 - 2²⁰ = 255572497 is a prime.

It is not a weakly prime, because it can be changed into another prime (256621093) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128310536 + 128310537.

It is an arithmetic number, because the mean of its divisors is an integer number (128310537).

Almost surely, 2^256621073 is an apocalyptic number.

It is an amenable number.

256621073 is a deficient number, since it is larger than the sum of its proper divisors (1).

256621073 is an equidigital number, since it uses as much as digits as its factorization.

256621073 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 15120, while the sum is 32.

The square root of 256621073 is about 16019.3967739113. The cubic root of 256621073 is about 635.4734914782.

The spelling of 256621073 in words is "two hundred fifty-six million, six hundred twenty-one thousand, seventy-three".