21122221020 has 24 divisors (see below), whose sum is σ = 59142219024. Its totient is φ = 5632592256.

The previous prime is 21122221019. The next prime is 21122221033. The reversal of 21122221020 is 2012222112.

It is a super-2 number, since 2×21122221020² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (15).

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, 176018449 + ... + 176018568.

It is an arithmetic number, because the mean of its divisors is an integer number (2464259126).

Almost surely, 2^21122221020 is an apocalyptic number.

21122221020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21122221020 is an abundant number, since it is smaller than the sum of its proper divisors (38019998004).

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

21122221020 is a wasteful number, since it uses less digits than its factorization.

21122221020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 352037029 (or 352037027 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 15.

Adding to 21122221020 its reverse (2012222112), we get a palindrome (23134443132).

The spelling of 21122221020 in words is "twenty-one billion, one hundred twenty-two million, two hundred twenty-one thousand, twenty".