256634436671 has 2 divisors, whose sum is σ = 256634436672. Its totient is φ = 256634436670.

The previous prime is 256634436637. The next prime is 256634436673. The reversal of 256634436671 is 176634436652.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-256634436671 is a prime.

It is a super-2 number, since 2×256634436671² (a number of 24 digits) contains 22 as substring.

Together with 256634436673, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (256634436673) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128317218335 + 128317218336.

It is an arithmetic number, because the mean of its divisors is an integer number (128317218336).

Almost surely, 2^256634436671 is an apocalyptic number.

256634436671 is a deficient number, since it is larger than the sum of its proper divisors (1).

256634436671 is an equidigital number, since it uses as much as digits as its factorization.

256634436671 is an evil number, because the sum of its binary digits is even.

The product of its digits is 13063680, while the sum is 53.

The spelling of 256634436671 in words is "two hundred fifty-six billion, six hundred thirty-four million, four hundred thirty-six thousand, six hundred seventy-one".