256872173 has 2 divisors, whose sum is σ = 256872174. Its totient is φ = 256872172.

The previous prime is 256872163. The next prime is 256872223. The reversal of 256872173 is 371278652.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 218951209 + 37920964 = 14797^2 + 6158^2 .

It is a cyclic number.

It is not a de Polignac number, because 256872173 - 2⁴ = 256872157 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 256872173.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (256872163) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 128436086 + 128436087.

It is an arithmetic number, because the mean of its divisors is an integer number (128436087).

Almost surely, 2^256872173 is an apocalyptic number.

It is an amenable number.

256872173 is a deficient number, since it is larger than the sum of its proper divisors (1).

256872173 is an equidigital number, since it uses as much as digits as its factorization.

256872173 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 141120, while the sum is 41.

The square root of 256872173 is about 16027.2322314241. The cubic root of 256872173 is about 635.6806911122.

The spelling of 256872173 in words is "two hundred fifty-six million, eight hundred seventy-two thousand, one hundred seventy-three".