256766399 has 4 divisors (see below), whose sum is σ = 270280440. Its totient is φ = 243252360.

The previous prime is 256766381. The next prime is 256766413. The reversal of 256766399 is 993667652.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 256766399 - 2⁸ = 256766143 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 256766399.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (256766309) 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, 6756992 + ... + 6757029.

It is an arithmetic number, because the mean of its divisors is an integer number (67570110).

Almost surely, 2^256766399 is an apocalyptic number.

256766399 is a deficient number, since it is larger than the sum of its proper divisors (13514041).

256766399 is a wasteful number, since it uses less digits than its factorization.

256766399 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13514040.

The product of its digits is 3674160, while the sum is 53.

The square root of 256766399 is about 16023.9320705000. The cubic root of 256766399 is about 635.5934262808.

The spelling of 256766399 in words is "two hundred fifty-six million, seven hundred sixty-six thousand, three hundred ninety-nine".