21222001220020 has 12 divisors (see below), whose sum is σ = 44566202562084. Its totient is φ = 8488800488000.

The previous prime is 21222001220009. The next prime is 21222001220033. The reversal of 21222001220020 is 2002210022212.

It can be written as a sum of positive squares in 2 ways, for example, as 11278662490384 + 9943338729636 = 3358372^2 + 3153306^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21222001219976 and 21222001220003.

It is a congruent number.

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, 530550030481 + ... + 530550030520.

It is an arithmetic number, because the mean of its divisors is an integer number (3713850213507).

Almost surely, 2^{21222001220020} is an apocalyptic number.

21222001220020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21222001220020 is an abundant number, since it is smaller than the sum of its proper divisors (23344201342064).

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

21222001220020 is a wasteful number, since it uses less digits than its factorization.

21222001220020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1061100061010 (or 1061100061008 counting only the distinct ones).

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

Adding to 21222001220020 its reverse (2002210022212), we get a palindrome (23224211242232).

The spelling of 21222001220020 in words is "twenty-one trillion, two hundred twenty-two billion, one million, two hundred twenty thousand, twenty".