21100202100 has 108 divisors (see below), whose sum is σ = 66353711424. Its totient is φ = 5608319040.

The previous prime is 21100202059. The next prime is 21100202117. The reversal of 21100202100 is 120200112.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a congruent number.

It is an unprimeable number.

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 35 ways as a sum of consecutive naturals, for example, 238117 + ... + 314483.

Almost surely, 2^21100202100 is an apocalyptic number.

21100202100 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 21100202100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33176855712).

21100202100 is an abundant number, since it is smaller than the sum of its proper divisors (45253509324).

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

21100202100 is a wasteful number, since it uses less digits than its factorization.

21100202100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 76694 (or 76684 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

Adding to 21100202100 its reverse (120200112), we get a palindrome (21220402212).

The spelling of 21100202100 in words is "twenty-one billion, one hundred million, two hundred two thousand, one hundred".