21202002100 has 36 divisors (see below), whose sum is σ = 46020383500. Its totient is φ = 8478581760.

The previous prime is 21202002083. The next prime is 21202002119. The reversal of 21202002100 is 120020212.

It can be written as a sum of positive squares in 6 ways, for example, as 2641754404 + 18560247696 = 51398^2 + 136236^2 .

It is a Harshad number since it is a multiple of its sum of digits (10).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 387226 + ... + 438574.

Almost surely, 2^21202002100 is an apocalyptic number.

21202002100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21202002100 is an abundant number, since it is smaller than the sum of its proper divisors (24818381400).

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

21202002100 is a wasteful number, since it uses less digits than its factorization.

21202002100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55492 (or 55485 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 10.

Adding to 21202002100 its reverse (120020212), we get a palindrome (21322022312).

The spelling of 21202002100 in words is "twenty-one billion, two hundred two million, two thousand, one hundred".