21311313312 has 96 divisors (see below), whose sum is σ = 57106969920. Its totient is φ = 6956881920.

The previous prime is 21311313281. The next prime is 21311313329. The reversal of 21311313312 is 21331311312.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (96).

It is a nude number because it is divisible by every one of its digits.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1356639 + ... + 1372257.

It is an arithmetic number, because the mean of its divisors is an integer number (594864270).

Almost surely, 2^21311313312 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 21311313312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28553484960).

21311313312 is an abundant number, since it is smaller than the sum of its proper divisors (35795656608).

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

21311313312 is a wasteful number, since it uses less digits than its factorization.

21311313312 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15926 (or 15918 counting only the distinct ones).

The product of its digits is 324, while the sum is 21.

Adding to 21311313312 its reverse (21331311312), we get a palindrome (42642624624).

The spelling of 21311313312 in words is "twenty-one billion, three hundred eleven million, three hundred thirteen thousand, three hundred twelve".