640068402 has 16 divisors (see below), whose sum is σ = 1314735552. Its totient is φ = 207589680.

The previous prime is 640068397. The next prime is 640068421. The reversal of 640068402 is 204860046.

It is a self number, because there is not a number n which added to its sum of digits gives 640068402.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1441374 + ... + 1441817.

It is an arithmetic number, because the mean of its divisors is an integer number (82170972).

Almost surely, 2^640068402 is an apocalyptic number.

640068402 is an abundant number, since it is smaller than the sum of its proper divisors (674667150).

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

640068402 is a wasteful number, since it uses less digits than its factorization.

640068402 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2883233.

The product of its (nonzero) digits is 9216, while the sum is 30.

The square root of 640068402 is about 25299.5731584547. The cubic root of 640068402 is about 861.8045765111.

The spelling of 640068402 in words is "six hundred forty million, sixty-eight thousand, four hundred two".