639636480 has 352 divisors, whose sum is σ = 2601818880. Its totient is φ = 145981440.

The previous prime is 639636479. The next prime is 639636581. The reversal of 639636480 is 84636936.

639636480 is a `hidden beast` number, since 6 + 3 + 9 + 636 + 4 + 8 + 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 31 ways as a sum of consecutive naturals, for example, 967350 + ... + 968010.

Almost surely, 2^639636480 is an apocalyptic number.

639636480 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 639636480, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1300909440).

639636480 is an abundant number, since it is smaller than the sum of its proper divisors (1962182400).

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

639636480 is a wasteful number, since it uses less digits than its factorization.

639636480 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 702 (or 678 counting only the distinct ones).

The product of its (nonzero) digits is 559872, while the sum is 45.

The square root of 639636480 is about 25291.0355659866. The cubic root of 639636480 is about 861.6106825904.

The spelling of 639636480 in words is "six hundred thirty-nine million, six hundred thirty-six thousand, four hundred eighty".