256061621 has 2 divisors, whose sum is σ = 256061622. Its totient is φ = 256061620.

The previous prime is 256061587. The next prime is 256061627. The reversal of 256061621 is 126160652.

256061621 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 245079025 + 10982596 = 15655^2 + 3314^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-256061621 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (256061627) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128030810 + 128030811.

It is an arithmetic number, because the mean of its divisors is an integer number (128030811).

Almost surely, 2^256061621 is an apocalyptic number.

It is an amenable number.

256061621 is a deficient number, since it is larger than the sum of its proper divisors (1).

256061621 is an equidigital number, since it uses as much as digits as its factorization.

256061621 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4320, while the sum is 29.

The square root of 256061621 is about 16001.9255403842. The cubic root of 256061621 is about 635.0113631794.

The spelling of 256061621 in words is "two hundred fifty-six million, sixty-one thousand, six hundred twenty-one".