21321231232 has 128 divisors (see below), whose sum is σ = 50139936000. Its totient is φ = 9026035200.

The previous prime is 21321231229. The next prime is 21321231233. The reversal of 21321231232 is 23213212312.

It is a tau number, because it is divible by the number of its divisors (128).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21321231233) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3641107 + ... + 3646957.

It is an arithmetic number, because the mean of its divisors is an integer number (391718250).

Almost surely, 2^21321231232 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 21321231232, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25069968000).

21321231232 is an abundant number, since it is smaller than the sum of its proper divisors (28818704768).

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

21321231232 is an frugal number, since it uses more digits than its factorization.

21321231232 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5969 (or 5943 counting only the distinct ones).

The product of its digits is 864, while the sum is 22.

Adding to 21321231232 its reverse (23213212312), we get a palindrome (44534443544).

The spelling of 21321231232 in words is "twenty-one billion, three hundred twenty-one million, two hundred thirty-one thousand, two hundred thirty-two".