640406508 has 48 divisors (see below), whose sum is σ = 1753914624. Its totient is φ = 178027200.

The previous prime is 640406491. The next prime is 640406509. The reversal of 640406508 is 805604046.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (640406509) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 99918 + ... + 106133.

It is an arithmetic number, because the mean of its divisors is an integer number (36539888).

Almost surely, 2^640406508 is an apocalyptic number.

It is an amenable number.

640406508 is an abundant number, since it is smaller than the sum of its proper divisors (1113508116).

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

640406508 is a wasteful number, since it uses less digits than its factorization.

640406508 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 206102 (or 206100 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 33.

The square root of 640406508 is about 25306.2543257591. The cubic root of 640406508 is about 861.9562946745.

The spelling of 640406508 in words is "six hundred forty million, four hundred six thousand, five hundred eight".