21321612312 has 192 divisors, whose sum is σ = 72112131840. Its totient is φ = 5112011520.

The previous prime is 21321612241. The next prime is 21321612317.

21321612312 is nontrivially palindromic in base 10.

It is a super-2 number, since 2×21321612312² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (24).

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21321612317) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 223923 + ... + 304605.

It is an arithmetic number, because the mean of its divisors is an integer number (375584020).

Almost surely, 2^21321612312 is an apocalyptic number.

21321612312 is a gapful number since it is divisible by the number (22) 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 21321612312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36056065920).

21321612312 is an abundant number, since it is smaller than the sum of its proper divisors (50790519528).

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

21321612312 is a wasteful number, since it uses less digits than its factorization.

21321612312 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80734 (or 80719 counting only the distinct ones).

The product of its digits is 864, while the sum is 24.

The spelling of 21321612312 in words is "twenty-one billion, three hundred twenty-one million, six hundred twelve thousand, three hundred twelve".