21003212100 has 72 divisors (see below), whose sum is σ = 65443866880. Its totient is φ = 5170020480.

The previous prime is 21003212077. The next prime is 21003212137. The reversal of 21003212100 is 121230012.

It is a super-2 number, since 2×21003212100² (a number of 21 digits) contains 22 as substring.

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

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, 2688820 + ... + 2696619.

Almost surely, 2^21003212100 is an apocalyptic number.

21003212100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21003212100 is an abundant number, since it is smaller than the sum of its proper divisors (44440654780).

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

21003212100 is a wasteful number, since it uses less digits than its factorization.

21003212100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5385469 (or 5385462 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 12.

Adding to 21003212100 its reverse (121230012), we get a palindrome (21124442112).

The spelling of 21003212100 in words is "twenty-one billion, three million, two hundred twelve thousand, one hundred".