256621621 has 8 divisors (see below), whose sum is σ = 263908800. Its totient is φ = 249432480.

The previous prime is 256621577. The next prime is 256621633. The reversal of 256621621 is 126126652.

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

It is a cyclic number.

It is not a de Polignac number, because 256621621 - 2¹³ = 256613429 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 (256621921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19185 + ... + 29686.

It is an arithmetic number, because the mean of its divisors is an integer number (32988600).

Almost surely, 2^256621621 is an apocalyptic number.

It is an amenable number.

256621621 is a deficient number, since it is larger than the sum of its proper divisors (7287179).

256621621 is an equidigital number, since it uses as much as digits as its factorization.

256621621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49019.

The product of its digits is 8640, while the sum is 31.

The square root of 256621621 is about 16019.4138781667. The cubic root of 256621621 is about 635.4739438173.

The spelling of 256621621 in words is "two hundred fifty-six million, six hundred twenty-one thousand, six hundred twenty-one".