256145216155391 has 2 divisors, whose sum is σ = 256145216155392. Its totient is φ = 256145216155390.

The previous prime is 256145216155343. The next prime is 256145216155541. The reversal of 256145216155391 is 193551612541652.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 256145216155391 - 2⁶ = 256145216155327 is a prime.

It is a super-2 number, since 2×256145216155391² (a number of 30 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (256145216155331) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128072608077695 + 128072608077696.

It is an arithmetic number, because the mean of its divisors is an integer number (128072608077696).

Almost surely, 2^{256145216155391} is an apocalyptic number.

256145216155391 is a deficient number, since it is larger than the sum of its proper divisors (1).

256145216155391 is an equidigital number, since it uses as much as digits as its factorization.

256145216155391 is an evil number, because the sum of its binary digits is even.

The product of its digits is 9720000, while the sum is 56.

The spelling of 256145216155391 in words is "two hundred fifty-six trillion, one hundred forty-five billion, two hundred sixteen million, one hundred fifty-five thousand, three hundred ninety-one".