257720520 has 64 divisors (see below), whose sum is σ = 806785920. Its totient is φ = 65736704.

The previous prime is 257720513. The next prime is 257720531. The reversal of 257720520 is 25027752.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 43929 + ... + 49448.

It is an arithmetic number, because the mean of its divisors is an integer number (12606030).

Almost surely, 2^257720520 is an apocalyptic number.

257720520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

257720520 is an abundant number, since it is smaller than the sum of its proper divisors (549065400).

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

257720520 is a wasteful number, since it uses less digits than its factorization.

257720520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 93414 (or 93410 counting only the distinct ones).

The product of its (nonzero) digits is 9800, while the sum is 30.

The square root of 257720520 is about 16053.6762144999. The cubic root of 257720520 is about 636.3797226113.

The spelling of 257720520 in words is "two hundred fifty-seven million, seven hundred twenty thousand, five hundred twenty".