21242315231 has 8 divisors (see below), whose sum is σ = 21284054400. Its totient is φ = 21200601240.

The previous prime is 21242315207. The next prime is 21242315243. The reversal of 21242315231 is 13251324212.

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-21242315231 is a prime.

It is a super-2 number, since 2×21242315231² (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 21242315231.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21242315251) 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, 2942216 + ... + 2949426.

It is an arithmetic number, because the mean of its divisors is an integer number (2660506800).

Almost surely, 2^21242315231 is an apocalyptic number.

21242315231 is a deficient number, since it is larger than the sum of its proper divisors (41739169).

21242315231 is an equidigital number, since it uses as much as digits as its factorization.

21242315231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12589.

The product of its digits is 2880, while the sum is 26.

Adding to 21242315231 its reverse (13251324212), we get a palindrome (34493639443).

The spelling of 21242315231 in words is "twenty-one billion, two hundred forty-two million, three hundred fifteen thousand, two hundred thirty-one".