639281984 has 28 divisors (see below), whose sum is σ = 1383901728. Its totient is φ = 290582400.

The previous prime is 639281947. The next prime is 639282011. The reversal of 639281984 is 489182936.

It is a happy number.

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, 453332 + ... + 454739.

Almost surely, 2^639281984 is an apocalyptic number.

639281984 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

It is an amenable number.

639281984 is an abundant number, since it is smaller than the sum of its proper divisors (744619744).

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

639281984 is a wasteful number, since it uses less digits than its factorization.

639281984 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 908094 (or 908084 counting only the distinct ones).

The product of its digits is 746496, while the sum is 50.

The square root of 639281984 is about 25284.0262616538. The cubic root of 639281984 is about 861.4514807138.

The spelling of 639281984 in words is "six hundred thirty-nine million, two hundred eighty-one thousand, nine hundred eighty-four".