6689643397 has 2 divisors, whose sum is σ = 6689643398. Its totient is φ = 6689643396.

The previous prime is 6689643383. The next prime is 6689643413. The reversal of 6689643397 is 7933469866.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 3412195396 + 3277448001 = 58414^2 + 57249^2 .

It is a cyclic number.

It is not a de Polignac number, because 6689643397 - 2¹¹ = 6689641349 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6389643397) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3344821698 + 3344821699.

It is an arithmetic number, because the mean of its divisors is an integer number (3344821699).

Almost surely, 2^6689643397 is an apocalyptic number.

It is an amenable number.

6689643397 is a deficient number, since it is larger than the sum of its proper divisors (1).

6689643397 is an equidigital number, since it uses as much as digits as its factorization.

6689643397 is an evil number, because the sum of its binary digits is even.

The product of its digits is 35271936, while the sum is 61.

The square root of 6689643397 is about 81790.2402307268. The cubic root of 6689643397 is about 1884.2317716079.

The spelling of 6689643397 in words is "six billion, six hundred eighty-nine million, six hundred forty-three thousand, three hundred ninety-seven".