21221111221020 has 240 divisors, whose sum is σ = 74197241062560. Its totient is φ = 5045762543616.

The previous prime is 21221111221019. The next prime is 21221111221043. The reversal of 21221111221020 is 2012211112212.

21221111221020 is a `hidden beast` number, since 212 + 211 + 1 + 1 + 221 + 0 + 20 = 666.

It is a super-2 number, since 2×21221111221020² (a number of 27 digits) contains 22 as substring.

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 = 21221111220984 and 21221111221002.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 19754529 + ... + 20801048.

It is an arithmetic number, because the mean of its divisors is an integer number (309155171094).

Almost surely, 2^{21221111221020} is an apocalyptic number.

21221111221020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21221111221020 is an abundant number, since it is smaller than the sum of its proper divisors (52976129841540).

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

21221111221020 is a wasteful number, since it uses less digits than its factorization.

21221111221020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40555634 (or 40555623 counting only the distinct ones).

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

Adding to 21221111221020 its reverse (2012211112212), we get a palindrome (23233322333232).

The spelling of 21221111221020 in words is "twenty-one trillion, two hundred twenty-one billion, one hundred eleven million, two hundred twenty-one thousand, twenty".