640270251 has 48 divisors (see below), whose sum is σ = 1010929920. Its totient is φ = 404157600.

The previous prime is 640270231. The next prime is 640270283. The reversal of 640270251 is 152072046.

640270251 is a `hidden beast` number, since 6 + 402 + 7 + 0 + 251 = 666.

It is not a de Polignac number, because 640270251 - 2¹⁵ = 640237483 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (640270231) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 608676 + ... + 609726.

It is an arithmetic number, because the mean of its divisors is an integer number (21061040).

Almost surely, 2^640270251 is an apocalyptic number.

640270251 is a deficient number, since it is larger than the sum of its proper divisors (370659669).

640270251 is a wasteful number, since it uses less digits than its factorization.

640270251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1198 (or 1186 counting only the distinct ones).

The product of its (nonzero) digits is 3360, while the sum is 27.

The square root of 640270251 is about 25303.5620219763. The cubic root of 640270251 is about 861.8951585534.

The spelling of 640270251 in words is "six hundred forty million, two hundred seventy thousand, two hundred fifty-one".