257666021688 has 32 divisors (see below), whose sum is σ = 646542063360. Its totient is φ = 85571739360.

The previous prime is 257666021677. The next prime is 257666021689. The reversal of 257666021688 is 886120666752.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (257666021689) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19801770 + ... + 19814777.

It is an arithmetic number, because the mean of its divisors is an integer number (20204439480).

Almost surely, 2^257666021688 is an apocalyptic number.

It is an amenable number.

257666021688 is an abundant number, since it is smaller than the sum of its proper divisors (388876041672).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

257666021688 is a wasteful number, since it uses less digits than its factorization.

257666021688 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39616827 (or 39616823 counting only the distinct ones).

The product of its (nonzero) digits is 11612160, while the sum is 57.

The spelling of 257666021688 in words is "two hundred fifty-seven billion, six hundred sixty-six million, twenty-one thousand, six hundred eighty-eight".