255666817 has 4 divisors (see below), whose sum is σ = 292190656. Its totient is φ = 219142980.

The previous prime is 255666787. The next prime is 255666823. The reversal of 255666817 is 718666552.

255666817 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, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a de Polignac number, because none of the positive numbers 2^k-255666817 is a prime.

It is a super-2 number, since 2×255666817² = 130731042629822978, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (255666847) 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, 18261909 + ... + 18261922.

It is an arithmetic number, because the mean of its divisors is an integer number (73047664).

Almost surely, 2^255666817 is an apocalyptic number.

It is an amenable number.

255666817 is a deficient number, since it is larger than the sum of its proper divisors (36523839).

255666817 is an equidigital number, since it uses as much as digits as its factorization.

255666817 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36523838.

The product of its digits is 604800, while the sum is 46.

The square root of 255666817 is about 15989.5846412594. The cubic root of 255666817 is about 634.6848350256.

The spelling of 255666817 in words is "two hundred fifty-five million, six hundred sixty-six thousand, eight hundred seventeen".