21002212100 has 72 divisors (see below), whose sum is σ = 46183919040. Its totient is φ = 8288874880.

The previous prime is 21002212093. The next prime is 21002212169. The reversal of 21002212100 is 121220012.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 10149866 + ... + 10151934.

It is an arithmetic number, because the mean of its divisors is an integer number (641443320).

Almost surely, 2^21002212100 is an apocalyptic number.

21002212100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21002212100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23091959520).

21002212100 is an abundant number, since it is smaller than the sum of its proper divisors (25181706940).

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

21002212100 is a wasteful number, since it uses less digits than its factorization.

21002212100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3389 (or 3382 counting only the distinct ones).

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

Adding to 21002212100 its reverse (121220012), we get a palindrome (21123432112).

The spelling of 21002212100 in words is "twenty-one billion, two million, two hundred twelve thousand, one hundred".