255661657 has 4 divisors (see below), whose sum is σ = 270700596. Its totient is φ = 240622720.

The previous prime is 255661643. The next prime is 255661661. The reversal of 255661657 is 756166552.

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 75672601 + 179989056 = 8699^2 + 13416^2 .

It is a cyclic number.

It is not a de Polignac number, because 255661657 - 2¹⁹ = 255137369 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (255661607) 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, 7519444 + ... + 7519477.

It is an arithmetic number, because the mean of its divisors is an integer number (67675149).

Almost surely, 2^255661657 is an apocalyptic number.

It is an amenable number.

255661657 is a deficient number, since it is larger than the sum of its proper divisors (15038939).

255661657 is a wasteful number, since it uses less digits than its factorization.

255661657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15038938.

The product of its digits is 378000, while the sum is 43.

The square root of 255661657 is about 15989.4232854096. The cubic root of 255661657 is about 634.6805651510.

The spelling of 255661657 in words is "two hundred fifty-five million, six hundred sixty-one thousand, six hundred fifty-seven".