639959040 has 408 divisors, whose sum is σ = 2617225728. Its totient is φ = 141557760.

The previous prime is 639959029. The next prime is 639959053. The reversal of 639959040 is 40959936.

It is a happy number.

639959040 is a `hidden beast` number, since 639 + 9 + 5 + 9 + 0 + 4 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 20643825 + ... + 20643855.

Almost surely, 2^639959040 is an apocalyptic number.

639959040 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 639959040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1308612864).

639959040 is an abundant number, since it is smaller than the sum of its proper divisors (1977266688).

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

639959040 is an equidigital number, since it uses as much as digits as its factorization.

639959040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 81 (or 48 counting only the distinct ones).

The product of its (nonzero) digits is 262440, while the sum is 45.

The square root of 639959040 is about 25297.4117253129. The cubic root of 639959040 is about 861.7554911112.

The spelling of 639959040 in words is "six hundred thirty-nine million, nine hundred fifty-nine thousand, forty".