257801681 has 4 divisors (see below), whose sum is σ = 264769332. Its totient is φ = 250834032.

The previous prime is 257801657. The next prime is 257801683. The reversal of 257801681 is 186108752.

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 199798225 + 58003456 = 14135^2 + 7616^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-257801681 is a prime.

It is a super-2 number, since 2×257801681² = 132923413452851522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (257801683) 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, 3483770 + ... + 3483843.

It is an arithmetic number, because the mean of its divisors is an integer number (66192333).

Almost surely, 2^257801681 is an apocalyptic number.

It is an amenable number.

257801681 is a deficient number, since it is larger than the sum of its proper divisors (6967651).

257801681 is an equidigital number, since it uses as much as digits as its factorization.

257801681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6967650.

The product of its (nonzero) digits is 26880, while the sum is 38.

The square root of 257801681 is about 16056.2038165938. The cubic root of 257801681 is about 636.4465182159.

The spelling of 257801681 in words is "two hundred fifty-seven million, eight hundred one thousand, six hundred eighty-one".