257407691 has 4 divisors (see below), whose sum is σ = 259956384. Its totient is φ = 254859000.

The previous prime is 257407681. The next prime is 257407747. The reversal of 257407691 is 196704752.

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

It is a cyclic number.

It is not a de Polignac number, because 257407691 - 2⁶ = 257407627 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (257407681) by changing a digit.

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, 1274195 + ... + 1274396.

It is an arithmetic number, because the mean of its divisors is an integer number (64989096).

Almost surely, 2^257407691 is an apocalyptic number.

257407691 is a deficient number, since it is larger than the sum of its proper divisors (2548693).

257407691 is a wasteful number, since it uses less digits than its factorization.

257407691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2548692.

The product of its (nonzero) digits is 105840, while the sum is 41.

The square root of 257407691 is about 16043.9300359980. The cubic root of 257407691 is about 636.1221326768.

The spelling of 257407691 in words is "two hundred fifty-seven million, four hundred seven thousand, six hundred ninety-one".