21221220112220 has 24 divisors (see below), whose sum is σ = 45005795529408. Its totient is φ = 8404443608000.

The previous prime is 21221220112219. The next prime is 21221220112273. The reversal of 21221220112220 is 2221102212212.

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 = 21221220112192 and 21221220112201.

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, 5252775236 + ... + 5252779275.

It is an arithmetic number, because the mean of its divisors is an integer number (1875241480392).

Almost surely, 2^{21221220112220} is an apocalyptic number.

21221220112220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21221220112220 is an abundant number, since it is smaller than the sum of its proper divisors (23784575417188).

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

21221220112220 is a wasteful number, since it uses less digits than its factorization.

21221220112220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10505554621 (or 10505554619 counting only the distinct ones).

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

Adding to 21221220112220 its reverse (2221102212212), we get a palindrome (23442322324432).

The spelling of 21221220112220 in words is "twenty-one trillion, two hundred twenty-one billion, two hundred twenty million, one hundred twelve thousand, two hundred twenty".