21440324231 has 4 divisors (see below), whose sum is σ = 22701519792. Its totient is φ = 20179128672.

The previous prime is 21440324219. The next prime is 21440324237. The reversal of 21440324231 is 13242304412.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21440324231 is a prime.

It is a super-2 number, since 2×21440324231² (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 21440324231.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21440324237) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 630597755 + ... + 630597788.

It is an arithmetic number, because the mean of its divisors is an integer number (5675379948).

Almost surely, 2^21440324231 is an apocalyptic number.

21440324231 is a deficient number, since it is larger than the sum of its proper divisors (1261195561).

21440324231 is a wasteful number, since it uses less digits than its factorization.

21440324231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1261195560.

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

Adding to 21440324231 its reverse (13242304412), we get a palindrome (34682628643).

The spelling of 21440324231 in words is "twenty-one billion, four hundred forty million, three hundred twenty-four thousand, two hundred thirty-one".