21644115231 has 8 divisors (see below), whose sum is σ = 29529955840. Its totient is φ = 14093842392.

The previous prime is 21644115193. The next prime is 21644115307. The reversal of 21644115231 is 13251144612.

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

It is not a de Polignac number, because 21644115231 - 2⁶ = 21644115167 is a prime.

It is a super-2 number, since 2×21644115231² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21644125231) 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 7 ways as a sum of consecutive naturals, for example, 83891791 + ... + 83892048.

It is an arithmetic number, because the mean of its divisors is an integer number (3691244480).

Almost surely, 2^21644115231 is an apocalyptic number.

21644115231 is a deficient number, since it is larger than the sum of its proper divisors (7885840609).

21644115231 is a wasteful number, since it uses less digits than its factorization.

21644115231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 167783885.

The product of its digits is 5760, while the sum is 30.

Adding to 21644115231 its reverse (13251144612), we get a palindrome (34895259843).

The spelling of 21644115231 in words is "twenty-one billion, six hundred forty-four million, one hundred fifteen thousand, two hundred thirty-one".