21313313321 has 6 divisors (see below), whose sum is σ = 22640786430. Its totient is φ = 20059588736.

The previous prime is 21313313299. The next prime is 21313313353. The reversal of 21313313321 is 12331331312.

It can be written as a sum of positive squares in 3 ways, for example, as 8539792921 + 12773520400 = 92411^2 + 113020^2 .

It is not a de Polignac number, because 21313313321 - 2²⁶ = 21246204457 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21313363321) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 36873956 + ... + 36874533.

It is an arithmetic number, because the mean of its divisors is an integer number (3773464405).

Almost surely, 2^21313313321 is an apocalyptic number.

It is an amenable number.

21313313321 is a deficient number, since it is larger than the sum of its proper divisors (1327473109).

21313313321 is an equidigital number, since it uses as much as digits as its factorization.

21313313321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73748523 (or 73748506 counting only the distinct ones).

The product of its digits is 972, while the sum is 23.

Adding to 21313313321 its reverse (12331331312), we get a palindrome (33644644633).

The spelling of 21313313321 in words is "twenty-one billion, three hundred thirteen million, three hundred thirteen thousand, three hundred twenty-one".