638005000991 has 2 divisors, whose sum is σ = 638005000992. Its totient is φ = 638005000990.

The previous prime is 638005000957. The next prime is 638005001041. The reversal of 638005000991 is 199000500836.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 638005000991 - 2¹⁰ = 638004999967 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (638005000891) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319002500495 + 319002500496.

It is an arithmetic number, because the mean of its divisors is an integer number (319002500496).

Almost surely, 2^638005000991 is an apocalyptic number.

638005000991 is a deficient number, since it is larger than the sum of its proper divisors (1).

638005000991 is an equidigital number, since it uses as much as digits as its factorization.

638005000991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 58320, while the sum is 41.

The spelling of 638005000991 in words is "six hundred thirty-eight billion, five million, nine hundred ninety-one", and thus it is an aban number.