21221110212120 has 864 divisors, whose sum is σ = 91447571451600. Its totient is φ = 4241755994112.

The previous prime is 21221110212079. The next prime is 21221110212157. The reversal of 21221110212120 is 2121201112212.

21221110212120 is a `hidden beast` number, since 2 + 1 + 221 + 110 + 212 + 120 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 21221110212093 and 21221110212102.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 215 ways as a sum of consecutive naturals, for example, 56454714 + ... + 56829366.

Almost surely, 2^{21221110212120} is an apocalyptic number.

21221110212120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21221110212120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (45723785725800).

21221110212120 is an abundant number, since it is smaller than the sum of its proper divisors (70226461239480).

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

21221110212120 is a wasteful number, since it uses less digits than its factorization.

21221110212120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 374729 (or 374702 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 18.

Adding to 21221110212120 its reverse (2121201112212), we get a palindrome (23342311324332).

The spelling of 21221110212120 in words is "twenty-one trillion, two hundred twenty-one billion, one hundred ten million, two hundred twelve thousand, one hundred twenty".