21221120222100 has 108 divisors (see below), whose sum is σ = 68138774269020. Its totient is φ = 5520941836800.

The previous prime is 21221120222083. The next prime is 21221120222189. The reversal of 21221120222100 is 122202112212.

It is a happy number.

21221120222100 is a `hidden beast` number, since 2 + 1 + 221 + 120 + 222 + 100 = 666.

It can be written as a sum of positive squares in 6 ways, for example, as 1569116990736 + 19652003231364 = 1252644^2 + 4433058^2 .

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 287512155 + ... + 287585954.

It is an arithmetic number, because the mean of its divisors is an integer number (630914576565).

Almost surely, 2^{21221120222100} is an apocalyptic number.

21221120222100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21221120222100 is an abundant number, since it is smaller than the sum of its proper divisors (46917654046920).

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

21221120222100 is a wasteful number, since it uses less digits than its factorization.

21221120222100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 575098170 (or 575098160 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

Adding to 21221120222100 its reverse (122202112212), we get a palindrome (21343322334312).

The spelling of 21221120222100 in words is "twenty-one trillion, two hundred twenty-one billion, one hundred twenty million, two hundred twenty-two thousand, one hundred".