21201022020 has 48 divisors (see below), whose sum is σ = 59383634688. Its totient is φ = 5651627520.

The previous prime is 21201021991. The next prime is 21201022033. The reversal of 21201022020 is 2022010212.

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 = 21201021987 and 21201022005.

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, 115260 + ... + 235980.

It is an arithmetic number, because the mean of its divisors is an integer number (1237159056).

Almost surely, 2^21201022020 is an apocalyptic number.

21201022020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21201022020 is an abundant number, since it is smaller than the sum of its proper divisors (38182612668).

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

21201022020 is a wasteful number, since it uses less digits than its factorization.

21201022020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 123660 (or 123658 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 12.

Adding to 21201022020 its reverse (2022010212), we get a palindrome (23223032232).

The spelling of 21201022020 in words is "twenty-one billion, two hundred one million, twenty-two thousand, twenty".