21312121300 has 18 divisors (see below), whose sum is σ = 46247303438. Its totient is φ = 8524848480.

The previous prime is 21312121289. The next prime is 21312121351. The reversal of 21312121300 is 312121312.

It can be written as a sum of positive squares in 3 ways, for example, as 896283844 + 20415837456 = 29938^2 + 142884^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 106560507 + ... + 106560706.

Almost surely, 2^21312121300 is an apocalyptic number.

21312121300 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21312121300 is an abundant number, since it is smaller than the sum of its proper divisors (24935182138).

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

21312121300 is a wasteful number, since it uses less digits than its factorization.

21312121300 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 213121227 (or 213121220 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 16.

Adding to 21312121300 its reverse (312121312), we get a palindrome (21624242612).

The spelling of 21312121300 in words is "twenty-one billion, three hundred twelve million, one hundred twenty-one thousand, three hundred".