21312312023 has 4 divisors (see below), whose sum is σ = 21354183480. Its totient is φ = 21270440568.

The previous prime is 21312312017. The next prime is 21312312031. The reversal of 21312312023 is 32021321312.

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

It is a cyclic number.

It is not a de Polignac number, because 21312312023 - 2⁶ = 21312311959 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21312311986 and 21312312004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21312312083) 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 3 ways as a sum of consecutive naturals, for example, 20934965 + ... + 20935982.

It is an arithmetic number, because the mean of its divisors is an integer number (5338545870).

Almost surely, 2^21312312023 is an apocalyptic number.

21312312023 is a deficient number, since it is larger than the sum of its proper divisors (41871457).

21312312023 is an equidigital number, since it uses as much as digits as its factorization.

21312312023 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41871456.

The product of its (nonzero) digits is 432, while the sum is 20.

Adding to 21312312023 its reverse (32021321312), we get a palindrome (53333633335).

The spelling of 21312312023 in words is "twenty-one billion, three hundred twelve million, three hundred twelve thousand, twenty-three".