21329125920 has 216 divisors, whose sum is σ = 75214185228. Its totient is φ = 5503933440.

The previous prime is 21329125919. The next prime is 21329125933. The reversal of 21329125920 is 2952192312.

21329125920 is a `hidden beast` number, since 21 + 32 + 9 + 12 + 592 + 0 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 20940405264 + 388720656 = 144708^2 + 19716^2 .

It is a super-2 number, since 2×21329125920² (a number of 21 digits) contains 22 as substring.

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

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 1376134 + ... + 1391546.

Almost surely, 2^21329125920 is an apocalyptic number.

21329125920 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 21329125920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37607092614).

21329125920 is an abundant number, since it is smaller than the sum of its proper divisors (53885059308).

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

21329125920 is a wasteful number, since it uses less digits than its factorization.

21329125920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15496 (or 15454 counting only the distinct ones).

The product of its (nonzero) digits is 19440, while the sum is 36.

The spelling of 21329125920 in words is "twenty-one billion, three hundred twenty-nine million, one hundred twenty-five thousand, nine hundred twenty".