21002311020 has 48 divisors (see below), whose sum is σ = 62265678048. Its totient is φ = 5271168000.

The previous prime is 21002311019. The next prime is 21002311039. The reversal of 21002311020 is 2011320012.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a junction number, because it is equal to n+sod(n) for n = 21002310987 and 21002311005.

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, 10294231 + ... + 10296270.

It is an arithmetic number, because the mean of its divisors is an integer number (1297201626).

Almost surely, 2^21002311020 is an apocalyptic number.

21002311020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21002311020 is an abundant number, since it is smaller than the sum of its proper divisors (41263367028).

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

21002311020 is a wasteful number, since it uses less digits than its factorization.

21002311020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20590530 (or 20590528 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 12.

Adding to 21002311020 its reverse (2011320012), we get a palindrome (23013631032).

The spelling of 21002311020 in words is "twenty-one billion, two million, three hundred eleven thousand, twenty".