21345306313 has 2 divisors, whose sum is σ = 21345306314. Its totient is φ = 21345306312.

The previous prime is 21345306251. The next prime is 21345306319. The reversal of 21345306313 is 31360354312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21337029184 + 8277129 = 146072^2 + 2877^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21345306313 is a prime.

It is not a weakly prime, because it can be changed into another prime (21345306319) 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 as a sum of consecutive naturals, namely, 10672653156 + 10672653157.

It is an arithmetic number, because the mean of its divisors is an integer number (10672653157).

Almost surely, 2^21345306313 is an apocalyptic number.

It is an amenable number.

21345306313 is a deficient number, since it is larger than the sum of its proper divisors (1).

21345306313 is an equidigital number, since it uses as much as digits as its factorization.

21345306313 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 19440, while the sum is 31.

The spelling of 21345306313 in words is "twenty-one billion, three hundred forty-five million, three hundred six thousand, three hundred thirteen".