15721313 has 2 divisors, whose sum is σ = 15721314. Its totient is φ = 15721312.

The previous prime is 15721301. The next prime is 15721319. The reversal of 15721313 is 31312751.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11444689 + 4276624 = 3383^2 + 2068^2 .

It is an emirp because it is prime and its reverse (31312751) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 15721313 - 2⁶ = 15721249 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (15721319) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7860656 + 7860657.

It is an arithmetic number, because the mean of its divisors is an integer number (7860657).

Almost surely, 2^15721313 is an apocalyptic number.

It is an amenable number.

15721313 is a deficient number, since it is larger than the sum of its proper divisors (1).

15721313 is an equidigital number, since it uses as much as digits as its factorization.

15721313 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 630, while the sum is 23.

The square root of 15721313 is about 3965.0110970841. The cubic root of 15721313 is about 250.5126175081.

The spelling of 15721313 in words is "fifteen million, seven hundred twenty-one thousand, three hundred thirteen".