640237902 has 16 divisors (see below), whose sum is σ = 1284170112. Its totient is φ = 212796920.

The previous prime is 640237877. The next prime is 640237903. The reversal of 640237902 is 209732046.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640237903) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 151674 + ... + 155837.

It is an arithmetic number, because the mean of its divisors is an integer number (80260632).

Almost surely, 2^640237902 is an apocalyptic number.

640237902 is an abundant number, since it is smaller than the sum of its proper divisors (643932210).

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

640237902 is a wasteful number, since it uses less digits than its factorization.

640237902 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 307863.

The product of its (nonzero) digits is 18144, while the sum is 33.

The square root of 640237902 is about 25302.9227955981. The cubic root of 640237902 is about 861.8806428517.

Adding to 640237902 its reverse (209732046), we get a palindrome (849969948).

The spelling of 640237902 in words is "six hundred forty million, two hundred thirty-seven thousand, nine hundred two".