21000221222020 has 24 divisors (see below), whose sum is σ = 45621170242200. Its totient is φ = 8110430264832.

The previous prime is 21000221221979. The next prime is 21000221222033. The reversal of 21000221222020 is 2022212200012.

It can be written as a sum of positive squares in 4 ways, for example, as 5663724100164 + 15336497121856 = 2379858^2 + 3916184^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21000221221985 and 21000221222003.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 18103638405 + ... + 18103639564.

It is an arithmetic number, because the mean of its divisors is an integer number (1900882093425).

Almost surely, 2^{21000221222020} is an apocalyptic number.

21000221222020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21000221222020 is an abundant number, since it is smaller than the sum of its proper divisors (24620949020180).

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

21000221222020 is a wasteful number, since it uses less digits than its factorization.

21000221222020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36207278007 (or 36207278005 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 16.

Adding to 21000221222020 its reverse (2022212200012), we get a palindrome (23022433422032).

The spelling of 21000221222020 in words is "twenty-one trillion, two hundred twenty-one million, two hundred twenty-two thousand, twenty".