99999998639 has 2 divisors, whose sum is σ = 99999998640. Its totient is φ = 99999998638.

The previous prime is 99999998627. The next prime is 99999998641. The reversal of 99999998639 is 93689999999.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 99999998639 - 2¹² = 99999994543 is a prime.

It is a Sophie Germain prime.

Together with 99999998641, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (99999998339) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49999999319 + 49999999320.

It is an arithmetic number, because the mean of its divisors is an integer number (49999999320).

Almost surely, 2^99999998639 is an apocalyptic number.

99999998639 is a deficient number, since it is larger than the sum of its proper divisors (1).

99999998639 is an equidigital number, since it uses as much as digits as its factorization.

99999998639 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6198727824, while the sum is 89.

The spelling of 99999998639 in words is "ninety-nine billion, nine hundred ninety-nine million, nine hundred ninety-eight thousand, six hundred thirty-nine".