21022112100 has 72 divisors (see below), whose sum is σ = 66353440608. Its totient is φ = 5096268800.

The previous prime is 21022112077. The next prime is 21022112101. The reversal of 21022112100 is 121122012.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is not an unprimeable number, because it can be changed into a prime (21022112101) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3181869 + ... + 3188468.

It is an arithmetic number, because the mean of its divisors is an integer number (921575564).

Almost surely, 2^21022112100 is an apocalyptic number.

21022112100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21022112100 is an abundant number, since it is smaller than the sum of its proper divisors (45331328508).

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

21022112100 is a wasteful number, since it uses less digits than its factorization.

21022112100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6370365 (or 6370358 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 12.

Adding to 21022112100 its reverse (121122012), we get a palindrome (21143234112).

The spelling of 21022112100 in words is "twenty-one billion, twenty-two million, one hundred twelve thousand, one hundred".