21112221100 has 18 divisors (see below), whose sum is σ = 45813520004. Its totient is φ = 8444888400.

The previous prime is 21112221043. The next prime is 21112221101. The reversal of 21112221100 is 112221112.

It is not an unprimeable number, because it can be changed into a prime (21112221101) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 105561006 + ... + 105561205.

Almost surely, 2^21112221100 is an apocalyptic number.

21112221100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21112221100 is an abundant number, since it is smaller than the sum of its proper divisors (24701298904).

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

21112221100 is a wasteful number, since it uses less digits than its factorization.

21112221100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 211122225 (or 211122218 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 21112221100 its reverse (112221112), we get a palindrome (21224442212).

The spelling of 21112221100 in words is "twenty-one billion, one hundred twelve million, two hundred twenty-one thousand, one hundred".