21312179712 has 120 divisors (see below), whose sum is σ = 61641184176. Its totient is φ = 7088726016.

The previous prime is 21312179689. The next prime is 21312179719. The reversal of 21312179712 is 21797121312.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21312179719) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2239348 + ... + 2248844.

Almost surely, 2^21312179712 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21312179712, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30820592088).

21312179712 is an abundant number, since it is smaller than the sum of its proper divisors (40329004464).

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

21312179712 is an equidigital number, since it uses as much as digits as its factorization.

21312179712 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10008 (or 9989 counting only the distinct ones).

The product of its digits is 10584, while the sum is 36.

The spelling of 21312179712 in words is "twenty-one billion, three hundred twelve million, one hundred seventy-nine thousand, seven hundred twelve".