639116640 has 216 divisors, whose sum is σ = 2282651280. Its totient is φ = 162826752.

The previous prime is 639116633. The next prime is 639116657. The reversal of 639116640 is 46611936.

639116640 is a `hidden beast` number, since 6 + 3 + 9 + 1 + 1 + 6 + 640 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 639116595 and 639116604.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 761341 + ... + 762179.

It is an arithmetic number, because the mean of its divisors is an integer number (10567830).

Almost surely, 2^639116640 is an apocalyptic number.

639116640 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 639116640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1141325640).

639116640 is an abundant number, since it is smaller than the sum of its proper divisors (1643534640).

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

639116640 is a wasteful number, since it uses less digits than its factorization.

639116640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 906 (or 872 counting only the distinct ones).

The product of its (nonzero) digits is 23328, while the sum is 36.

The square root of 639116640 is about 25280.7563178003. The cubic root of 639116640 is about 861.3772056579.

The spelling of 639116640 in words is "six hundred thirty-nine million, one hundred sixteen thousand, six hundred forty".