639544140 has 96 divisors (see below), whose sum is σ = 1995840000. Its totient is φ = 170018496.

The previous prime is 639544127. The next prime is 639544189. The reversal of 639544140 is 41445936.

639544140 is a `hidden beast` number, since 639 + 5 + 4 + 4 + 14 + 0 = 666.

639544140 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 = 639544095 and 639544104.

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, 192211 + ... + 195509.

It is an arithmetic number, because the mean of its divisors is an integer number (20790000).

Almost surely, 2^639544140 is an apocalyptic number.

639544140 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 639544140, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (997920000).

639544140 is an abundant number, since it is smaller than the sum of its proper divisors (1356295860).

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

639544140 is a wasteful number, since it uses less digits than its factorization.

639544140 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3676 (or 3668 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 36.

The square root of 639544140 is about 25289.2099520724. The cubic root of 639544140 is about 861.5692189561.

The spelling of 639544140 in words is "six hundred thirty-nine million, five hundred forty-four thousand, one hundred forty".