20631409920 has 972 divisors, whose sum is σ = 84828426228. Its totient is φ = 4622745600.

The previous prime is 20631409919. The next prime is 20631409927. The reversal of 20631409920 is 2990413602.

It can be written as a sum of positive squares in 2 ways, for example, as 3623076864 + 17008333056 = 60192^2 + 130416^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20631409927) by changing a digit.

It is a polite number, since it can be written in 107 ways as a sum of consecutive naturals, for example, 503205100 + ... + 503205140.

Almost surely, 2^20631409920 is an apocalyptic number.

20631409920 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 20631409920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42414213114).

20631409920 is an abundant number, since it is smaller than the sum of its proper divisors (64197016308).

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

20631409920 is a wasteful number, since it uses less digits than its factorization.

20631409920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 128 (or 81 counting only the distinct ones).

The product of its (nonzero) digits is 23328, while the sum is 36.

The spelling of 20631409920 in words is "twenty billion, six hundred thirty-one million, four hundred nine thousand, nine hundred twenty".