257661697 has 4 divisors (see below), whose sum is σ = 257715540. Its totient is φ = 257607856.

The previous prime is 257661667. The next prime is 257661731. The reversal of 257661697 is 796166752.

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 92179201 + 165482496 = 9601^2 + 12864^2 .

It is a cyclic number.

It is not a de Polignac number, because 257661697 - 2¹⁹ = 257137409 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 257661697.

It is not an unprimeable number, because it can be changed into a prime (257661667) 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, 18958 + ... + 29575.

It is an arithmetic number, because the mean of its divisors is an integer number (64428885).

Almost surely, 2^257661697 is an apocalyptic number.

It is an amenable number.

257661697 is a deficient number, since it is larger than the sum of its proper divisors (53843).

257661697 is an equidigital number, since it uses as much as digits as its factorization.

257661697 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53842.

The product of its digits is 952560, while the sum is 49.

The square root of 257661697 is about 16051.8440373684. The cubic root of 257661697 is about 636.3313024431.

The spelling of 257661697 in words is "two hundred fifty-seven million, six hundred sixty-one thousand, six hundred ninety-seven".