21221223231 has 32 divisors (see below), whose sum is σ = 30784481280. Its totient is φ = 12925753344.

The previous prime is 21221223227. The next prime is 21221223281. The reversal of 21221223231 is 13232212212.

It is not a de Polignac number, because 21221223231 - 2² = 21221223227 is a prime.

It is a super-2 number, since 2×21221223231² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21221223198 and 21221223207.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21221223211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1549791 + ... + 1563423.

It is an arithmetic number, because the mean of its divisors is an integer number (962015040).

Almost surely, 2^21221223231 is an apocalyptic number.

21221223231 is a deficient number, since it is larger than the sum of its proper divisors (9563258049).

21221223231 is a wasteful number, since it uses less digits than its factorization.

21221223231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14055.

The product of its digits is 576, while the sum is 21.

Adding to 21221223231 its reverse (13232212212), we get a palindrome (34453435443).

The spelling of 21221223231 in words is "twenty-one billion, two hundred twenty-one million, two hundred twenty-three thousand, two hundred thirty-one".