640963208 has 12 divisors (see below), whose sum is σ = 1201940295. Its totient is φ = 320445800.

The previous prime is 640963177. The next prime is 640963217. The reversal of 640963208 is 802369046.

It is a powerful number, because all its prime factors have an exponent greater than 1 and also an Achilles number because it is not a perfect power.

It can be written as a sum of positive squares in only one way, i.e., 320481604 + 320481604 = 17902^2 + 17902^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=17902.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 67133 + ... + 76083.

Almost surely, 2^640963208 is an apocalyptic number.

It is an amenable number.

640963208 is a deficient number, since it is larger than the sum of its proper divisors (560977087).

640963208 is an frugal number, since it uses more digits than its factorization.

640963208 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17908 (or 8953 counting only the distinct ones).

The product of its (nonzero) digits is 62208, while the sum is 38.

The square root of 640963208 is about 25317.2511936031. The cubic root of 640963208 is about 862.2059861267.

The spelling of 640963208 in words is "six hundred forty million, nine hundred sixty-three thousand, two hundred eight".