256645783 has 4 divisors (see below), whose sum is σ = 256677840. Its totient is φ = 256613728.

The previous prime is 256645771. The next prime is 256645789. The reversal of 256645783 is 387546652.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-256645783 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256645789) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7263 + ... + 23791.

It is an arithmetic number, because the mean of its divisors is an integer number (64169460).

Almost surely, 2^256645783 is an apocalyptic number.

256645783 is a deficient number, since it is larger than the sum of its proper divisors (32057).

256645783 is a wasteful number, since it uses less digits than its factorization.

256645783 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32056.

The product of its digits is 1209600, while the sum is 46.

The square root of 256645783 is about 16020.1680078581. The cubic root of 256645783 is about 635.4938873688.

The spelling of 256645783 in words is "two hundred fifty-six million, six hundred forty-five thousand, seven hundred eighty-three".