21443240231 has 8 divisors (see below), whose sum is σ = 24507934080. Its totient is φ = 18378889848.

The previous prime is 21443240183. The next prime is 21443240251. The reversal of 21443240231 is 13204234412.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21443240231 is a prime.

It is a super-2 number, since 2×21443240231² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21443240231.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21443240251) 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, 65780 + ... + 217286.

It is an arithmetic number, because the mean of its divisors is an integer number (3063491760).

Almost surely, 2^21443240231 is an apocalyptic number.

21443240231 is a deficient number, since it is larger than the sum of its proper divisors (3064693849).

21443240231 is a wasteful number, since it uses less digits than its factorization.

21443240231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 171733.

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

Adding to 21443240231 its reverse (13204234412), we get a palindrome (34647474643).

The spelling of 21443240231 in words is "twenty-one billion, four hundred forty-three million, two hundred forty thousand, two hundred thirty-one".