21312345243 has 8 divisors (see below), whose sum is σ = 32475954688. Its totient is φ = 12178482984.

The previous prime is 21312345233. The next prime is 21312345281. The reversal of 21312345243 is 34254321312.

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

It is not a de Polignac number, because 21312345243 - 2⁵ = 21312345211 is a prime.

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 21312345243.

It is not an unprimeable number, because it can be changed into a prime (21312345233) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 507436771 + ... + 507436812.

It is an arithmetic number, because the mean of its divisors is an integer number (4059494336).

Almost surely, 2^21312345243 is an apocalyptic number.

21312345243 is a deficient number, since it is larger than the sum of its proper divisors (11163609445).

21312345243 is a wasteful number, since it uses less digits than its factorization.

21312345243 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1014873593.

The product of its digits is 17280, while the sum is 30.

Adding to 21312345243 its reverse (34254321312), we get a palindrome (55566666555).

The spelling of 21312345243 in words is "twenty-one billion, three hundred twelve million, three hundred forty-five thousand, two hundred forty-three".