21231320113 has 4 divisors (see below), whose sum is σ = 21262868068. Its totient is φ = 21199772160.

The previous prime is 21231320107. The next prime is 21231320153. The reversal of 21231320113 is 31102313212.

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 14555939904 + 6675380209 = 120648^2 + 81703^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21231320113 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21231320153) 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, 15772968 + ... + 15774313.

It is an arithmetic number, because the mean of its divisors is an integer number (5315717017).

Almost surely, 2^21231320113 is an apocalyptic number.

It is an amenable number.

21231320113 is a deficient number, since it is larger than the sum of its proper divisors (31547955).

21231320113 is an equidigital number, since it uses as much as digits as its factorization.

21231320113 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31547954.

The product of its (nonzero) digits is 216, while the sum is 19.

Adding to 21231320113 its reverse (31102313212), we get a palindrome (52333633325).

The spelling of 21231320113 in words is "twenty-one billion, two hundred thirty-one million, three hundred twenty thousand, one hundred thirteen".