21321313232 has 80 divisors (see below), whose sum is σ = 44439936912. Its totient is φ = 9873653760.

The previous prime is 21321313217. The next prime is 21321313243. The reversal of 21321313232 is 23231312312.

It can be written as a sum of positive squares in 8 ways, for example, as 517289536 + 20804023696 = 22744^2 + 144236^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21321313198 and 21321313207.

It is a congruent number.

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, 11455982 + ... + 11457842.

Almost surely, 2^21321313232 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 21321313232, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22219968456).

21321313232 is an abundant number, since it is smaller than the sum of its proper divisors (23118623680).

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

21321313232 is a wasteful number, since it uses less digits than its factorization.

21321313232 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2536 (or 2530 counting only the distinct ones).

The product of its digits is 1296, while the sum is 23.

Adding to 21321313232 its reverse (23231312312), we get a palindrome (44552625544).

The spelling of 21321313232 in words is "twenty-one billion, three hundred twenty-one million, three hundred thirteen thousand, two hundred thirty-two".