21221212231 has 8 divisors (see below), whose sum is σ = 21956719680. Its totient is φ = 20485954272.

The previous prime is 21221212213. The next prime is 21221212247. The reversal of 21221212231 is 13221212212.

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

It is a cyclic number.

It is not a de Polignac number, because 21221212231 - 2²⁹ = 20684341319 is a prime.

It is a super-2 number, since 2×21221212231² (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 = 21221212199 and 21221212208.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21221212531) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 119746 + ... + 238288.

It is an arithmetic number, because the mean of its divisors is an integer number (2744589960).

Almost surely, 2^21221212231 is an apocalyptic number.

21221212231 is a deficient number, since it is larger than the sum of its proper divisors (735507449).

21221212231 is a wasteful number, since it uses less digits than its factorization.

21221212231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 124745.

The product of its digits is 192, while the sum is 19.

Subtracting from 21221212231 its sum of digits (19), we obtain a palindrome (21221212212).

Adding to 21221212231 its reverse (13221212212), we get a palindrome (34442424443).

The spelling of 21221212231 in words is "twenty-one billion, two hundred twenty-one million, two hundred twelve thousand, two hundred thirty-one".