21312312113 has 4 divisors (see below), whose sum is σ = 21604261668. Its totient is φ = 21020362560.

The previous prime is 21312312101. The next prime is 21312312143. The reversal of 21312312113 is 31121321312.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 16716421264 + 4595890849 = 129292^2 + 67793^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21312312113 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21312312143) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 145974668 + ... + 145974813.

It is an arithmetic number, because the mean of its divisors is an integer number (5401065417).

Almost surely, 2^21312312113 is an apocalyptic number.

It is an amenable number.

21312312113 is a deficient number, since it is larger than the sum of its proper divisors (291949555).

21312312113 is an equidigital number, since it uses as much as digits as its factorization.

21312312113 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 291949554.

The product of its digits is 216, while the sum is 20.

Adding to 21312312113 its reverse (31121321312), we get a palindrome (52433633425).

The spelling of 21312312113 in words is "twenty-one billion, three hundred twelve million, three hundred twelve thousand, one hundred thirteen".