6638684917 has 2 divisors, whose sum is σ = 6638684918. Its totient is φ = 6638684916.

The previous prime is 6638684891. The next prime is 6638684953. The reversal of 6638684917 is 7194868366.

It is a happy number.

6638684917 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 6240842001 + 397842916 = 78999^2 + 19946^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6638684917 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6638684957) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3319342458 + 3319342459.

It is an arithmetic number, because the mean of its divisors is an integer number (3319342459).

Almost surely, 2^6638684917 is an apocalyptic number.

It is an amenable number.

6638684917 is a deficient number, since it is larger than the sum of its proper divisors (1).

6638684917 is an equidigital number, since it uses as much as digits as its factorization.

6638684917 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10450944, while the sum is 58.

The square root of 6638684917 is about 81478.1253895793. The cubic root of 6638684917 is about 1879.4351816347.

The spelling of 6638684917 in words is "six billion, six hundred thirty-eight million, six hundred eighty-four thousand, nine hundred seventeen".