256623173 has 2 divisors, whose sum is σ = 256623174. Its totient is φ = 256623172.

The previous prime is 256623151. The next prime is 256623187. The reversal of 256623173 is 371326652.

256623173 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 193293409 + 63329764 = 13903^2 + 7958^2 .

It is a cyclic number.

It is not a de Polignac number, because 256623173 - 2⁸ = 256622917 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (256623193) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128311586 + 128311587.

It is an arithmetic number, because the mean of its divisors is an integer number (128311587).

Almost surely, 2^256623173 is an apocalyptic number.

It is an amenable number.

256623173 is a deficient number, since it is larger than the sum of its proper divisors (1).

256623173 is an equidigital number, since it uses as much as digits as its factorization.

256623173 is an evil number, because the sum of its binary digits is even.

The product of its digits is 45360, while the sum is 35.

The square root of 256623173 is about 16019.4623193165. The cubic root of 256623173 is about 635.4752248909.

The spelling of 256623173 in words is "two hundred fifty-six million, six hundred twenty-three thousand, one hundred seventy-three".