639449673696 has 720 divisors, whose sum is σ = 2139237611280. Its totient is φ = 186653859840.

The previous prime is 639449673671. The next prime is 639449673719. The reversal of 639449673696 is 696376944936.

639449673696 is a `hidden beast` number, since 6 + 3 + 9 + 4 + 496 + 73 + 69 + 6 = 666.

639449673696 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 (72).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 119 ways as a sum of consecutive naturals, for example, 970333015 + ... + 970333673.

It is an arithmetic number, because the mean of its divisors is an integer number (2971163349).

Almost surely, 2^639449673696 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 639449673696, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1069618805640).

639449673696 is an abundant number, since it is smaller than the sum of its proper divisors (1499787937584).

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

639449673696 is a wasteful number, since it uses less digits than its factorization.

639449673696 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 797 (or 761 counting only the distinct ones).

The product of its digits is 952342272, while the sum is 72.

The spelling of 639449673696 in words is "six hundred thirty-nine billion, four hundred forty-nine million, six hundred seventy-three thousand, six hundred ninety-six".