640605371 has 12 divisors (see below), whose sum is σ = 754177032. Its totient is φ = 542471328.

The previous prime is 640605319. The next prime is 640605377. The reversal of 640605371 is 173506046.

It is not a de Polignac number, because 640605371 - 2¹⁸ = 640343227 is a prime.

It is not an unprimeable number, because it can be changed into a prime (640605377) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 74690 + ... + 82823.

It is an arithmetic number, because the mean of its divisors is an integer number (62848086).

Almost surely, 2^640605371 is an apocalyptic number.

640605371 is a deficient number, since it is larger than the sum of its proper divisors (113571661).

640605371 is a wasteful number, since it uses less digits than its factorization.

640605371 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 157610 (or 157603 counting only the distinct ones).

The product of its (nonzero) digits is 15120, while the sum is 32.

The square root of 640605371 is about 25310.1831482903. The cubic root of 640605371 is about 862.0455054456.

The spelling of 640605371 in words is "six hundred forty million, six hundred five thousand, three hundred seventy-one".