255921517 has 4 divisors (see below), whose sum is σ = 255959100. Its totient is φ = 255883936.

The previous prime is 255921503. The next prime is 255921521. The reversal of 255921517 is 715129552.

255921517 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It can be written as a sum of positive squares in 2 ways, for example, as 90516196 + 165405321 = 9514^2 + 12861^2 .

It is a cyclic number.

It is not a de Polignac number, because 255921517 - 2²⁷ = 121703789 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 (255927517) 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, 5392 + ... + 23257.

It is an arithmetic number, because the mean of its divisors is an integer number (63989775).

Almost surely, 2^255921517 is an apocalyptic number.

It is an amenable number.

255921517 is a deficient number, since it is larger than the sum of its proper divisors (37583).

255921517 is an equidigital number, since it uses as much as digits as its factorization.

255921517 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37582.

The product of its digits is 31500, while the sum is 37.

The square root of 255921517 is about 15997.5472182457. The cubic root of 255921517 is about 634.8955266569.

The spelling of 255921517 in words is "two hundred fifty-five million, nine hundred twenty-one thousand, five hundred seventeen".