21224243231 has 6 divisors (see below), whose sum is σ = 21265330896. Its totient is φ = 21183234800.

The previous prime is 21224243219. The next prime is 21224243233. The reversal of 21224243231 is 13234242212.

It is not a de Polignac number, because 21224243231 - 2⁶ = 21224243167 is a prime.

It is a super-2 number, since 2×21224243231² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21224243231.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21224243233) 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 5 ways as a sum of consecutive naturals, for example, 232346 + ... + 310536.

It is an arithmetic number, because the mean of its divisors is an integer number (3544221816).

Almost surely, 2^21224243231 is an apocalyptic number.

21224243231 is a deficient number, since it is larger than the sum of its proper divisors (41087665).

21224243231 is an frugal number, since it uses more digits than its factorization.

21224243231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 79233 (or 78712 counting only the distinct ones).

The product of its digits is 4608, while the sum is 26.

Adding to 21224243231 its reverse (13234242212), we get a palindrome (34458485443).

The spelling of 21224243231 in words is "twenty-one billion, two hundred twenty-four million, two hundred forty-three thousand, two hundred thirty-one".