256399823 has 2 divisors, whose sum is σ = 256399824. Its totient is φ = 256399822.

The previous prime is 256399807. The next prime is 256399861. The reversal of 256399823 is 328993652.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 256399823 - 2⁴ = 256399807 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (256399873) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128199911 + 128199912.

It is an arithmetic number, because the mean of its divisors is an integer number (128199912).

Almost surely, 2^256399823 is an apocalyptic number.

256399823 is a deficient number, since it is larger than the sum of its proper divisors (1).

256399823 is an equidigital number, since it uses as much as digits as its factorization.

256399823 is an evil number, because the sum of its binary digits is even.

The product of its digits is 699840, while the sum is 47.

The square root of 256399823 is about 16012.4895940638. The cubic root of 256399823 is about 635.2908110588.

The spelling of 256399823 in words is "two hundred fifty-six million, three hundred ninety-nine thousand, eight hundred twenty-three".