21312003100 has 72 divisors (see below), whose sum is σ = 47066827808. Its totient is φ = 8374060800.

The previous prime is 21312003019. The next prime is 21312003149. The reversal of 21312003100 is 130021312.

It is a super-2 number, since 2×21312003100² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5896894 + ... + 5900506.

Almost surely, 2^21312003100 is an apocalyptic number.

21312003100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21312003100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23533413904).

21312003100 is an abundant number, since it is smaller than the sum of its proper divisors (25754824708).

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

21312003100 is a wasteful number, since it uses less digits than its factorization.

21312003100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4655 (or 4648 counting only the distinct ones).

The product of its (nonzero) digits is 36, while the sum is 13.

Adding to 21312003100 its reverse (130021312), we get a palindrome (21442024412).

The spelling of 21312003100 in words is "twenty-one billion, three hundred twelve million, three thousand, one hundred".