20721076731904 has 204 divisors, whose sum is σ = 43529368009176. Its totient is φ = 9862676217856.

The previous prime is 20721076731811. The next prime is 20721076731913. The reversal of 20721076731904 is 40913767012702.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 7869758172 + ... + 7869760804.

Almost surely, 2^{20721076731904} 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 20721076731904, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21764684004588).

20721076731904 is an abundant number, since it is smaller than the sum of its proper divisors (22808291277272).

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

20721076731904 is an frugal number, since it uses more digits than its factorization.

20721076731904 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2938 (or 2885 counting only the distinct ones).

The product of its (nonzero) digits is 889056, while the sum is 49.

The spelling of 20721076731904 in words is "twenty trillion, seven hundred twenty-one billion, seventy-six million, seven hundred thirty-one thousand, nine hundred four".