256621051640507 has 2 divisors, whose sum is σ = 256621051640508. Its totient is φ = 256621051640506.

The previous prime is 256621051640461. The next prime is 256621051640509. The reversal of 256621051640507 is 705046150126652.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 256621051640507 - 2¹⁴ = 256621051624123 is a prime.

Together with 256621051640509, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (256621051640509) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128310525820253 + 128310525820254.

It is an arithmetic number, because the mean of its divisors is an integer number (128310525820254).

Almost surely, 2^{256621051640507} is an apocalyptic number.

256621051640507 is a deficient number, since it is larger than the sum of its proper divisors (1).

256621051640507 is an equidigital number, since it uses as much as digits as its factorization.

256621051640507 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3024000, while the sum is 50.

The spelling of 256621051640507 in words is "two hundred fifty-six trillion, six hundred twenty-one billion, fifty-one million, six hundred forty thousand, five hundred seven".