21221111222120 has 64 divisors (see below), whose sum is σ = 48212601390720. Its totient is φ = 8405765086464.

The previous prime is 21221111222119. The next prime is 21221111222123. The reversal of 21221111222120 is 2122211112212.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 21221111222092 and 21221111222101.

It is not an unprimeable number, because it can be changed into a prime (21221111222123) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 174804482 + ... + 174925838.

It is an arithmetic number, because the mean of its divisors is an integer number (753321896730).

Almost surely, 2^{21221111222120} is an apocalyptic number.

21221111222120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21221111222120 is an abundant number, since it is smaller than the sum of its proper divisors (26991490168600).

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

21221111222120 is a wasteful number, since it uses less digits than its factorization.

21221111222120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 163914 (or 163910 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 20.

Adding to 21221111222120 its reverse (2122211112212), we get a palindrome (23343322334332).

The spelling of 21221111222120 in words is "twenty-one trillion, two hundred twenty-one billion, one hundred eleven million, two hundred twenty-two thousand, one hundred twenty".