639448680 has 96 divisors (see below), whose sum is σ = 2077328160. Its totient is φ = 157397760.

The previous prime is 639448643. The next prime is 639448721. The reversal of 639448680 is 86844936.

It is a super-2 number, since 2×639448680² = 817789228707484800, which contains 22 as substring.

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, 4515 + ... + 36045.

It is an arithmetic number, because the mean of its divisors is an integer number (21638835).

Almost surely, 2^639448680 is an apocalyptic number.

639448680 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 639448680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1038664080).

639448680 is an abundant number, since it is smaller than the sum of its proper divisors (1437879480).

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

639448680 is a wasteful number, since it uses less digits than its factorization.

639448680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31571 (or 31554 counting only the distinct ones).

The product of its (nonzero) digits is 995328, while the sum is 48.

The square root of 639448680 is about 25287.3225154424. The cubic root of 639448680 is about 861.5263501453.

The spelling of 639448680 in words is "six hundred thirty-nine million, four hundred forty-eight thousand, six hundred eighty".