257757421 has 4 divisors (see below), whose sum is σ = 260414812. Its totient is φ = 255100032.

The previous prime is 257757403. The next prime is 257757427. The reversal of 257757421 is 124757752.

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 92352100 + 165405321 = 9610^2 + 12861^2 .

It is a cyclic number.

It is not a de Polignac number, because 257757421 - 2⁷ = 257757293 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 (257757427) 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, 1328550 + ... + 1328743.

It is an arithmetic number, because the mean of its divisors is an integer number (65103703).

Almost surely, 2^257757421 is an apocalyptic number.

It is an amenable number.

257757421 is a deficient number, since it is larger than the sum of its proper divisors (2657391).

257757421 is an equidigital number, since it uses as much as digits as its factorization.

257757421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2657390.

The product of its digits is 137200, while the sum is 40.

The square root of 257757421 is about 16054.8254739813. The cubic root of 257757421 is about 636.4100939187.

The spelling of 257757421 in words is "two hundred fifty-seven million, seven hundred fifty-seven thousand, four hundred twenty-one".