21200402100 has 72 divisors (see below), whose sum is σ = 61822931968. Its totient is φ = 5608915200.

The previous prime is 21200402089. The next prime is 21200402107. The reversal of 21200402100 is 120400212.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21200402107) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 240121 + ... + 316320.

Almost surely, 2^21200402100 is an apocalyptic number.

21200402100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21200402100 is an abundant number, since it is smaller than the sum of its proper divisors (40622529868).

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

21200402100 is a wasteful number, since it uses less digits than its factorization.

21200402100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 556585 (or 556578 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 12.

Adding to 21200402100 its reverse (120400212), we get a palindrome (21320802312).

The spelling of 21200402100 in words is "twenty-one billion, two hundred million, four hundred two thousand, one hundred".