20639120640 has 576 divisors, whose sum is σ = 72922332672. Its totient is φ = 4954521600.

The previous prime is 20639120617. The next prime is 20639120651. The reversal of 20639120640 is 4602193602.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 282727644 + ... + 282727716.

It is an arithmetic number, because the mean of its divisors is an integer number (126601272).

Almost surely, 2^20639120640 is an apocalyptic number.

20639120640 is a gapful number since it is divisible by the number (20) 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 20639120640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36461166336).

20639120640 is an abundant number, since it is smaller than the sum of its proper divisors (52283212032).

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

20639120640 is a wasteful number, since it uses less digits than its factorization.

20639120640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 246 (or 232 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 33.

The spelling of 20639120640 in words is "twenty billion, six hundred thirty-nine million, one hundred twenty thousand, six hundred forty".