21312121000000 has 98 divisors (see below), whose sum is σ = 52863375957314. Its totient is φ = 8524848000000.

The previous prime is 21312120999989. The next prime is 21312121000021. The reversal of 21312121000000 is 12121312.

It can be written as a sum of positive squares in 7 ways, for example, as 20804983317504 + 507137682496 = 4561248^2 + 712136^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 13 ways as a sum of consecutive naturals, for example, 9656061 + ... + 11656060.

Almost surely, 2^{21312121000000} is an apocalyptic number.

21312121000000 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21312121000000 is an abundant number, since it is smaller than the sum of its proper divisors (31551254957314).

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

21312121000000 is an frugal number, since it uses more digits than its factorization.

21312121000000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21312163 (or 21312128 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 13.

Adding to 21312121000000 its reverse (12121312), we get a palindrome (21312133121312).

The spelling of 21312121000000 in words is "twenty-one trillion, three hundred twelve billion, one hundred twenty-one million", and thus it is an aban number.