6721331317 has 2 divisors, whose sum is σ = 6721331318. Its totient is φ = 6721331316.

The previous prime is 6721331291. The next prime is 6721331329. The reversal of 6721331317 is 7131331276.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 4980689476 + 1740641841 = 70574^2 + 41721^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6721331317 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6721331387) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3360665658 + 3360665659.

It is an arithmetic number, because the mean of its divisors is an integer number (3360665659).

Almost surely, 2^6721331317 is an apocalyptic number.

It is an amenable number.

6721331317 is a deficient number, since it is larger than the sum of its proper divisors (1).

6721331317 is an equidigital number, since it uses as much as digits as its factorization.

6721331317 is an evil number, because the sum of its binary digits is even.

The product of its digits is 15876, while the sum is 34.

The square root of 6721331317 is about 81983.7259277718. The cubic root of 6721331317 is about 1887.2022018781.

The spelling of 6721331317 in words is "six billion, seven hundred twenty-one million, three hundred thirty-one thousand, three hundred seventeen".