257661655 has 4 divisors (see below), whose sum is σ = 309193992. Its totient is φ = 206129320.

The previous prime is 257661643. The next prime is 257661667. The reversal of 257661655 is 556166752.

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

It is an interprime number because it is at equal distance from previous prime (257661643) and next prime (257661667).

It is not a de Polignac number, because 257661655 - 2⁵ = 257661623 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

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 in 3 ways as a sum of consecutive naturals, for example, 25766161 + ... + 25766170.

It is an arithmetic number, because the mean of its divisors is an integer number (77298498).

Almost surely, 2^257661655 is an apocalyptic number.

257661655 is a deficient number, since it is larger than the sum of its proper divisors (51532337).

257661655 is an equidigital number, since it uses as much as digits as its factorization.

257661655 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51532336.

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

The square root of 257661655 is about 16051.8427291075. The cubic root of 257661655 is about 636.3312678681.

The spelling of 257661655 in words is "two hundred fifty-seven million, six hundred sixty-one thousand, six hundred fifty-five".