639461329920 has 880 divisors, whose sum is σ = 2636499317760. Its totient is φ = 145177214976.

The previous prime is 639461329849. The next prime is 639461329931. The reversal of 639461329920 is 29923164936.

639461329920 is a `hidden beast` number, since 63 + 9 + 461 + 32 + 9 + 92 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 484807021 + ... + 484808339.

It is an arithmetic number, because the mean of its divisors is an integer number (2996021952).

Almost surely, 2^639461329920 is an apocalyptic number.

639461329920 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 639461329920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1318249658880).

639461329920 is an abundant number, since it is smaller than the sum of its proper divisors (1997037987840).

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

639461329920 is a wasteful number, since it uses less digits than its factorization.

639461329920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1530 (or 1503 counting only the distinct ones).

The product of its (nonzero) digits is 3779136, while the sum is 54.

The spelling of 639461329920 in words is "six hundred thirty-nine billion, four hundred sixty-one million, three hundred twenty-nine thousand, nine hundred twenty".