21112212211220 has 24 divisors (see below), whose sum is σ = 47746079924424. Its totient is φ = 7795278354816.

The previous prime is 21112212211163. The next prime is 21112212211289. The reversal of 21112212211220 is 2211221221112.

It can be written as a sum of positive squares in 4 ways, for example, as 732386793616 + 20379825417604 = 855796^2 + 4514402^2 .

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 = 21112212211192 and 21112212211201.

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, 40600407839 + ... + 40600408358.

It is an arithmetic number, because the mean of its divisors is an integer number (1989419996851).

Almost surely, 2^{21112212211220} is an apocalyptic number.

21112212211220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21112212211220 is an abundant number, since it is smaller than the sum of its proper divisors (26633867713204).

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

21112212211220 is a wasteful number, since it uses less digits than its factorization.

21112212211220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 81200816219 (or 81200816217 counting only the distinct ones).

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

Adding to 21112212211220 its reverse (2211221221112), we get a palindrome (23323433432332).

The spelling of 21112212211220 in words is "twenty-one trillion, one hundred twelve billion, two hundred twelve million, two hundred eleven thousand, two hundred twenty".