21331221231 has 8 divisors (see below), whose sum is σ = 28598765104. Its totient is φ = 14142245760.

The previous prime is 21331221217. The next prime is 21331221271. The reversal of 21331221231 is 13212213312.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21331221231 - 2²³ = 21322832623 is a prime.

It is a super-2 number, since 2×21331221231² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21331221198 and 21331221207.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21331221271) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19641466 + ... + 19642551.

It is an arithmetic number, because the mean of its divisors is an integer number (3574845638).

Almost surely, 2^21331221231 is an apocalyptic number.

21331221231 is a deficient number, since it is larger than the sum of its proper divisors (7267543873).

21331221231 is a wasteful number, since it uses less digits than its factorization.

21331221231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39284201.

The product of its digits is 432, while the sum is 21.

Adding to 21331221231 its reverse (13212213312), we get a palindrome (34543434543).

The spelling of 21331221231 in words is "twenty-one billion, three hundred thirty-one million, two hundred twenty-one thousand, two hundred thirty-one".