21213320232 has 64 divisors (see below), whose sum is σ = 57256980480. Its totient is φ = 6510696192.

The previous prime is 21213320221. The next prime is 21213320237. The reversal of 21213320232 is 23202331212.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 21213320199 and 21213320208.

It is not an unprimeable number, because it can be changed into a prime (21213320237) 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, 38233 + ... + 209495.

It is an arithmetic number, because the mean of its divisors is an integer number (894640320).

Almost surely, 2^21213320232 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 21213320232, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28628490240).

21213320232 is an abundant number, since it is smaller than the sum of its proper divisors (36043660248).

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

21213320232 is a wasteful number, since it uses less digits than its factorization.

21213320232 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 171682 (or 171678 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 21.

Adding to 21213320232 its reverse (23202331212), we get a palindrome (44415651444).

The spelling of 21213320232 in words is "twenty-one billion, two hundred thirteen million, three hundred twenty thousand, two hundred thirty-two".