257345661 has 4 divisors (see below), whose sum is σ = 343127552. Its totient is φ = 171563772.

The previous prime is 257345653. The next prime is 257345707. The reversal of 257345661 is 166543752.

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 not a de Polignac number, because 257345661 - 2³ = 257345653 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 (257345651) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 42890941 + ... + 42890946.

It is an arithmetic number, because the mean of its divisors is an integer number (85781888).

Almost surely, 2^257345661 is an apocalyptic number.

It is an amenable number.

257345661 is a deficient number, since it is larger than the sum of its proper divisors (85781891).

257345661 is an equidigital number, since it uses as much as digits as its factorization.

257345661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 85781890.

The product of its digits is 151200, while the sum is 39.

The square root of 257345661 is about 16041.9967896768. The cubic root of 257345661 is about 636.0710310881.

The spelling of 257345661 in words is "two hundred fifty-seven million, three hundred forty-five thousand, six hundred sixty-one".