21312123000000 has 392 divisors, whose sum is σ = 80553798898176. Its totient is φ = 4871337600000.

The previous prime is 21312122999983. The next prime is 21312123000013. The reversal of 21312123000000 is 32121312.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is an unprimeable number.

It is a polite number, since it can be written in 55 ways as a sum of consecutive naturals, for example, 20492569 + ... + 21507431.

Almost surely, 2^{21312123000000} is an apocalyptic number.

21312123000000 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 21312123000000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40276899449088).

21312123000000 is an abundant number, since it is smaller than the sum of its proper divisors (59241675898176).

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

21312123000000 is an frugal number, since it uses more digits than its factorization.

21312123000000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1014915 (or 1014880 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 15.

Adding to 21312123000000 its reverse (32121312), we get a palindrome (21312155121312).

The spelling of 21312123000000 in words is "twenty-one trillion, three hundred twelve billion, one hundred twenty-three million", and thus it is an aban number.