21221121022220 has 24 divisors (see below), whose sum is σ = 50930690453664. Its totient is φ = 7275812921856.

The previous prime is 21221121022219. The next prime is 21221121022229. The reversal of 21221121022220 is 2222012112212.

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 = 21221121022192 and 21221121022201.

It is not an unprimeable number, because it can be changed into a prime (21221121022229) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 75789717797 + ... + 75789718076.

It is an arithmetic number, because the mean of its divisors is an integer number (2122112102236).

Almost surely, 2^{21221121022220} is an apocalyptic number.

21221121022220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21221121022220 is an abundant number, since it is smaller than the sum of its proper divisors (29709569431444).

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

21221121022220 is a wasteful number, since it uses less digits than its factorization.

21221121022220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 151579435889 (or 151579435887 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 20.

Adding to 21221121022220 its reverse (2222012112212), we get a palindrome (23443133134432).

The spelling of 21221121022220 in words is "twenty-one trillion, two hundred twenty-one billion, one hundred twenty-one million, twenty-two thousand, two hundred twenty".