21200100 has 36 divisors (see below), whose sum is σ = 61339824. Its totient is φ = 5653280.

The previous prime is 21200093. The next prime is 21200117. The reversal of 21200100 is 100212.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (6).

It is a super Niven number, because it is divisible the sum of any subset of its (nonzero) digits.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 35034 + ... + 35633.

It is an arithmetic number, because the mean of its divisors is an integer number (1703884).

Almost surely, 2^21200100 is an apocalyptic number.

21200100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21200100 is an abundant number, since it is smaller than the sum of its proper divisors (40139724).

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

21200100 is a wasteful number, since it uses less digits than its factorization.

21200100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 70684 (or 70677 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 6.

The square root of 21200100 is about 4604.3566325818. The cubic root of 21200100 is about 276.7659358941.

Adding to 21200100 its reverse (100212), we get a palindrome (21300312).

The spelling of 21200100 in words is "twenty-one million, two hundred thousand, one hundred".