21121221112220 has 24 divisors (see below), whose sum is σ = 44355224382000. Its totient is φ = 8448362721792.

The previous prime is 21121221112181. The next prime is 21121221112231. The reversal of 21121221112220 is 2221112212112.

It is a super-2 number, since 2×21121221112220² (a number of 27 digits) contains 22 as substring.

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 = 21121221112192 and 21121221112201.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6474170 + ... + 9173729.

It is an arithmetic number, because the mean of its divisors is an integer number (1848134349250).

Almost surely, 2^{21121221112220} is an apocalyptic number.

21121221112220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21121221112220 is an abundant number, since it is smaller than the sum of its proper divisors (23234003269780).

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

21121221112220 is a wasteful number, since it uses less digits than its factorization.

21121221112220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15715397 (or 15715395 counting only the distinct ones).

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

Adding to 21121221112220 its reverse (2221112212112), we get a palindrome (23342333324332).

The spelling of 21121221112220 in words is "twenty-one trillion, one hundred twenty-one billion, two hundred twenty-one million, one hundred twelve thousand, two hundred twenty".