256642943 has 2 divisors, whose sum is σ = 256642944. Its totient is φ = 256642942.

The previous prime is 256642933. The next prime is 256642949. The reversal of 256642943 is 349246652.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 256642943 - 2⁶ = 256642879 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 256642943.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (256642949) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128321471 + 128321472.

It is an arithmetic number, because the mean of its divisors is an integer number (128321472).

Almost surely, 2^256642943 is an apocalyptic number.

256642943 is a deficient number, since it is larger than the sum of its proper divisors (1).

256642943 is an equidigital number, since it uses as much as digits as its factorization.

256642943 is an evil number, because the sum of its binary digits is even.

The product of its digits is 311040, while the sum is 41.

The square root of 256642943 is about 16020.0793693415. The cubic root of 256642943 is about 635.4915432699.

The spelling of 256642943 in words is "two hundred fifty-six million, six hundred forty-two thousand, nine hundred forty-three".