257808997 has 4 divisors (see below), whose sum is σ = 262035436. Its totient is φ = 253582560.

The previous prime is 257808983. The next prime is 257809003. The reversal of 257808997 is 799808752.

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 29224836 + 228584161 = 5406^2 + 15119^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-257808997 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 (257808977) 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, 2113128 + ... + 2113249.

It is an arithmetic number, because the mean of its divisors is an integer number (65508859).

Almost surely, 2^257808997 is an apocalyptic number.

It is an amenable number.

257808997 is a deficient number, since it is larger than the sum of its proper divisors (4226439).

257808997 is an equidigital number, since it uses as much as digits as its factorization.

257808997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4226438.

The product of its (nonzero) digits is 2540160, while the sum is 55.

The square root of 257808997 is about 16056.4316396888. The cubic root of 257808997 is about 636.4525386042.

The spelling of 257808997 in words is "two hundred fifty-seven million, eight hundred eight thousand, nine hundred ninety-seven".