257285312640 has 96 divisors (see below), whose sum is σ = 888438365100. Its totient is φ = 68609415168.

The previous prime is 257285312573. The next prime is 257285312659. The reversal of 257285312640 is 46213582752.

257285312640 is a `hidden beast` number, since 2 + 5 + 72 + 8 + 531 + 2 + 6 + 40 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 254669603904 + 2615708736 = 504648^2 + 51144^2 .

It is a tau number, because it is divible by the number of its divisors (96).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 22328035 + ... + 22339554.

Almost surely, 2^257285312640 is an apocalyptic number.

257285312640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

257285312640 is an abundant number, since it is smaller than the sum of its proper divisors (631153052460).

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

257285312640 is a wasteful number, since it uses less digits than its factorization.

257285312640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44667614 (or 44667599 counting only the distinct ones).

The product of its (nonzero) digits is 806400, while the sum is 45.

The spelling of 257285312640 in words is "two hundred fifty-seven billion, two hundred eighty-five million, three hundred twelve thousand, six hundred forty".