21112021220 has 24 divisors (see below), whose sum is σ = 44337996024. Its totient is φ = 8444284416.

The previous prime is 21112021201. The next prime is 21112021237. The reversal of 21112021220 is 2212021112.

It can be written as a sum of positive squares in 4 ways, for example, as 15613502116 + 5498519104 = 124954^2 + 74152^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21112021195 and 21112021204.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 553484 + ... + 590396.

It is an arithmetic number, because the mean of its divisors is an integer number (1847416501).

Almost surely, 2^21112021220 is an apocalyptic number.

21112021220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21112021220 is an abundant number, since it is smaller than the sum of its proper divisors (23225974804).

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

21112021220 is a wasteful number, since it uses less digits than its factorization.

21112021220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 65519 (or 65517 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 21112021220 its reverse (2212021112), we get a palindrome (23324042332).

The spelling of 21112021220 in words is "twenty-one billion, one hundred twelve million, twenty-one thousand, two hundred twenty".