21220111220 has 72 divisors (see below), whose sum is σ = 55979048832. Its totient is φ = 6614055360.

The previous prime is 21220111181. The next prime is 21220111223. The reversal of 21220111220 is 2211102212.

It is a Harshad number since it is a multiple of its sum of digits (14).

It is a junction number, because it is equal to n+sod(n) for n = 21220111195 and 21220111204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21220111223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 609392 + ... + 643271.

Almost surely, 2^21220111220 is an apocalyptic number.

21220111220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21220111220 is an abundant number, since it is smaller than the sum of its proper divisors (34758937612).

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

21220111220 is a wasteful number, since it uses less digits than its factorization.

21220111220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1252701 (or 1252688 counting only the distinct ones).

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

Adding to 21220111220 its reverse (2211102212), we get a palindrome (23431213432).

The spelling of 21220111220 in words is "twenty-one billion, two hundred twenty million, one hundred eleven thousand, two hundred twenty".