21220021100 has 18 divisors (see below), whose sum is σ = 46047446004. Its totient is φ = 8488008400.

The previous prime is 21220021073. The next prime is 21220021157. The reversal of 21220021100 is 112002212.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 106100006 + ... + 106100205.

Almost surely, 2^21220021100 is an apocalyptic number.

21220021100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21220021100 is an abundant number, since it is smaller than the sum of its proper divisors (24827424904).

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

21220021100 is a wasteful number, since it uses less digits than its factorization.

21220021100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 212200225 (or 212200218 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 11.

Adding to 21220021100 its reverse (112002212), we get a palindrome (21332023312).

The spelling of 21220021100 in words is "twenty-one billion, two hundred twenty million, twenty-one thousand, one hundred".