639887040 has 392 divisors, whose sum is σ = 2471946288. Its totient is φ = 156764160.

The previous prime is 639886879. The next prime is 639887047. The reversal of 639887040 is 40788936.

It is a happy number.

639887040 is a `hidden beast` number, since 639 + 8 + 8 + 7 + 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 not an unprimeable number, because it can be changed into a prime (639887047) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 55 ways as a sum of consecutive naturals, for example, 3032535 + ... + 3032745.

Almost surely, 2^639887040 is an apocalyptic number.

639887040 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 639887040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1235973144).

639887040 is an abundant number, since it is smaller than the sum of its proper divisors (1832059248).

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

639887040 is a wasteful number, since it uses less digits than its factorization.

639887040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 259 (or 234 counting only the distinct ones).

The product of its (nonzero) digits is 290304, while the sum is 45.

The square root of 639887040 is about 25295.9886147982. The cubic root of 639887040 is about 861.7231719998.

The spelling of 639887040 in words is "six hundred thirty-nine million, eight hundred eighty-seven thousand, forty".