639718662 has 64 divisors (see below), whose sum is σ = 1424314368. Its totient is φ = 189924000.

The previous prime is 639718649. The next prime is 639718663. The reversal of 639718662 is 266817936.

It is a super-2 number, since 2×639718662² = 818479933022140488, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639718663) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 988423 + ... + 989069.

It is an arithmetic number, because the mean of its divisors is an integer number (22254912).

Almost surely, 2^639718662 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 639718662, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (712157184).

639718662 is an abundant number, since it is smaller than the sum of its proper divisors (784595706).

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

639718662 is a wasteful number, since it uses less digits than its factorization.

639718662 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 945.

The product of its digits is 653184, while the sum is 48.

The square root of 639718662 is about 25292.6602396822. The cubic root of 639718662 is about 861.6475815994.

The spelling of 639718662 in words is "six hundred thirty-nine million, seven hundred eighteen thousand, six hundred sixty-two".