21221102020 has 12 divisors (see below), whose sum is σ = 44564314284. Its totient is φ = 8488440800.

The previous prime is 21221101963. The next prime is 21221102087. The reversal of 21221102020 is 2020112212.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 13769614336 + 7451487684 = 117344^2 + 86322^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 530527531 + ... + 530527570.

It is an arithmetic number, because the mean of its divisors is an integer number (3713692857).

Almost surely, 2^21221102020 is an apocalyptic number.

21221102020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21221102020 is an abundant number, since it is smaller than the sum of its proper divisors (23343212264).

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

21221102020 is a wasteful number, since it uses less digits than its factorization.

21221102020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1061055110 (or 1061055108 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 13.

Adding to 21221102020 its reverse (2020112212), we get a palindrome (23241214232).

The spelling of 21221102020 in words is "twenty-one billion, two hundred twenty-one million, one hundred two thousand, twenty".