21512323100 has 18 divisors (see below), whose sum is σ = 46681741344. Its totient is φ = 8604929200.

The previous prime is 21512323099. The next prime is 21512323109. The reversal of 21512323100 is 132321512.

It is a super-2 number, since 2×21512323100² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21512323109) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 107561516 + ... + 107561715.

Almost surely, 2^21512323100 is an apocalyptic number.

21512323100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21512323100 is an abundant number, since it is smaller than the sum of its proper divisors (25169418244).

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

21512323100 is a wasteful number, since it uses less digits than its factorization.

21512323100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 215123245 (or 215123238 counting only the distinct ones).

The product of its (nonzero) digits is 360, while the sum is 20.

Adding to 21512323100 its reverse (132321512), we get a palindrome (21644644612).

The spelling of 21512323100 in words is "twenty-one billion, five hundred twelve million, three hundred twenty-three thousand, one hundred".