640866424 has 16 divisors (see below), whose sum is σ = 1310863320. Its totient is φ = 291302880.

The previous prime is 640866419. The next prime is 640866439. The reversal of 640866424 is 424668046.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3641199 + ... + 3641374.

Almost surely, 2^640866424 is an apocalyptic number.

It is an amenable number.

640866424 is an abundant number, since it is smaller than the sum of its proper divisors (669996896).

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

640866424 is a wasteful number, since it uses less digits than its factorization.

640866424 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7282590 (or 7282586 counting only the distinct ones).

The product of its (nonzero) digits is 221184, while the sum is 40.

The square root of 640866424 is about 25315.3396975036. The cubic root of 640866424 is about 862.1625868886.

The spelling of 640866424 in words is "six hundred forty million, eight hundred sixty-six thousand, four hundred twenty-four".