21120002100 has 72 divisors (see below), whose sum is σ = 67896904320. Its totient is φ = 5631999840.

The previous prime is 21120002089. The next prime is 21120002117. The reversal of 21120002100 is 120002112.

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 23 ways as a sum of consecutive naturals, for example, 3908412 + ... + 3913811.

It is an arithmetic number, because the mean of its divisors is an integer number (943012560).

Almost surely, 2^21120002100 is an apocalyptic number.

21120002100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21120002100 is an abundant number, since it is smaller than the sum of its proper divisors (46776902220).

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

21120002100 is a wasteful number, since it uses less digits than its factorization.

21120002100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7822246 (or 7822233 counting only the distinct ones).

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

Adding to 21120002100 its reverse (120002112), we get a palindrome (21240004212).

The spelling of 21120002100 in words is "twenty-one billion, one hundred twenty million, two thousand, one hundred".