21221111121120 has 384 divisors, whose sum is σ = 75701670871680. Its totient is φ = 5550254161920.

The previous prime is 21221111121113. The next prime is 21221111121143. The reversal of 21221111121120 is 2112111112212.

It is a happy number.

21221111121120 is a `hidden beast` number, since 212 + 211 + 1 + 1 + 121 + 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 = 21221111121093 and 21221111121102.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 728307192 + ... + 728336328.

It is an arithmetic number, because the mean of its divisors is an integer number (197139767895).

Almost surely, 2^{21221111121120} is an apocalyptic number.

21221111121120 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 21221111121120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37850835435840).

21221111121120 is an abundant number, since it is smaller than the sum of its proper divisors (54480559750560).

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

21221111121120 is a wasteful number, since it uses less digits than its factorization.

21221111121120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32395 (or 32381 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 18.

Adding to 21221111121120 its reverse (2112111112212), we get a palindrome (23333222233332).

The spelling of 21221111121120 in words is "twenty-one trillion, two hundred twenty-one billion, one hundred eleven million, one hundred twenty-one thousand, one hundred twenty".