21222021020 has 24 divisors (see below), whose sum is σ = 45007498368. Its totient is φ = 8404760000.

The previous prime is 21222021011. The next prime is 21222021047. The reversal of 21222021020 is 2012022212.

It is a junction number, because it is equal to n+sod(n) for n = 21222020986 and 21222021004.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5250956 + ... + 5254995.

It is an arithmetic number, because the mean of its divisors is an integer number (1875312432).

Almost surely, 2^21222021020 is an apocalyptic number.

21222021020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21222021020 is an abundant number, since it is smaller than the sum of its proper divisors (23785477348).

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

21222021020 is a wasteful number, since it uses less digits than its factorization.

21222021020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10506061 (or 10506059 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 14.

Adding to 21222021020 its reverse (2012022212), we get a palindrome (23234043232).

The spelling of 21222021020 in words is "twenty-one billion, two hundred twenty-two million, twenty-one thousand, twenty".