6638998361 has 2 divisors, whose sum is σ = 6638998362. Its totient is φ = 6638998360.

The previous prime is 6638998337. The next prime is 6638998363. The reversal of 6638998361 is 1638998366.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 4825941961 + 1813056400 = 69469^2 + 42580^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6638998361 is a prime.

It is a Sophie Germain prime.

Together with 6638998363, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 6638998361.

It is not a weakly prime, because it can be changed into another prime (6638998363) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3319499180 + 3319499181.

It is an arithmetic number, because the mean of its divisors is an integer number (3319499181).

Almost surely, 2^6638998361 is an apocalyptic number.

It is an amenable number.

6638998361 is a deficient number, since it is larger than the sum of its proper divisors (1).

6638998361 is an equidigital number, since it uses as much as digits as its factorization.

6638998361 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10077696, while the sum is 59.

The square root of 6638998361 is about 81480.0488524645. The cubic root of 6638998361 is about 1879.4647602042.

The spelling of 6638998361 in words is "six billion, six hundred thirty-eight million, nine hundred ninety-eight thousand, three hundred sixty-one".