21232331220 has 96 divisors (see below), whose sum is σ = 63117508608. Its totient is φ = 5314516992.

The previous prime is 21232331213. The next prime is 21232331227. The reversal of 21232331220 is 2213323212.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21232331213) and next prime (21232331227).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21232331227) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 352557 + ... + 408363.

It is an arithmetic number, because the mean of its divisors is an integer number (657474048).

Almost surely, 2^21232331220 is an apocalyptic number.

21232331220 is a gapful number since it is divisible by the number (20) 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 21232331220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31558754304).

21232331220 is an abundant number, since it is smaller than the sum of its proper divisors (41885177388).

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

21232331220 is a wasteful number, since it uses less digits than its factorization.

21232331220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56209 (or 56207 counting only the distinct ones).

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

Adding to 21232331220 its reverse (2213323212), we get a palindrome (23445654432).

The spelling of 21232331220 in words is "twenty-one billion, two hundred thirty-two million, three hundred thirty-one thousand, two hundred twenty".