257291661 has 32 divisors (see below), whose sum is σ = 395366400. Its totient is φ = 147369600.

The previous prime is 257291633. The next prime is 257291663. The reversal of 257291661 is 166192752.

It is not a de Polignac number, because 257291661 - 2⁷ = 257291533 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (257291663) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 41065 + ... + 46913.

It is an arithmetic number, because the mean of its divisors is an integer number (12355200).

Almost surely, 2^257291661 is an apocalyptic number.

It is an amenable number.

257291661 is a deficient number, since it is larger than the sum of its proper divisors (138074739).

257291661 is a wasteful number, since it uses less digits than its factorization.

257291661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5937.

The product of its digits is 45360, while the sum is 39.

The square root of 257291661 is about 16040.3136191285. The cubic root of 257291661 is about 636.0265380920.

The spelling of 257291661 in words is "two hundred fifty-seven million, two hundred ninety-one thousand, six hundred sixty-one".