21102122100 has 72 divisors (see below), whose sum is σ = 64646987328. Its totient is φ = 5296217600.

The previous prime is 21102122099. The next prime is 21102122131. The reversal of 21102122100 is 122120112.

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

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, 2063736 + ... + 2073935.

It is an arithmetic number, because the mean of its divisors is an integer number (897874824).

Almost surely, 2^21102122100 is an apocalyptic number.

21102122100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21102122100 is an abundant number, since it is smaller than the sum of its proper divisors (43544865228).

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

21102122100 is a wasteful number, since it uses less digits than its factorization.

21102122100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4137705 (or 4137698 counting only the distinct ones).

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

Adding to 21102122100 its reverse (122120112), we get a palindrome (21224242212).

The spelling of 21102122100 in words is "twenty-one billion, one hundred two million, one hundred twenty-two thousand, one hundred".