21321013020 has 48 divisors (see below), whose sum is σ = 62840883840. Its totient is φ = 5386360896.

The previous prime is 21321012989. The next prime is 21321013033. The reversal of 21321013020 is 2031012312.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9350182 + ... + 9352461.

It is an arithmetic number, because the mean of its divisors is an integer number (1309185080).

Almost surely, 2^21321013020 is an apocalyptic number.

21321013020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21321013020 is an abundant number, since it is smaller than the sum of its proper divisors (41519870820).

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

21321013020 is a wasteful number, since it uses less digits than its factorization.

21321013020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18702674 (or 18702672 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 15.

Adding to 21321013020 its reverse (2031012312), we get a palindrome (23352025332).

The spelling of 21321013020 in words is "twenty-one billion, three hundred twenty-one million, thirteen thousand, twenty".