78724198999 has 2 divisors, whose sum is σ = 78724199000. Its totient is φ = 78724198998.

The previous prime is 78724198991. The next prime is 78724199011. The reversal of 78724198999 is 99989142787.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 78724198999 - 2³ = 78724198991 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78724198991) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39362099499 + 39362099500.

It is an arithmetic number, because the mean of its divisors is an integer number (39362099500).

Almost surely, 2^78724198999 is an apocalyptic number.

78724198999 is a deficient number, since it is larger than the sum of its proper divisors (1).

78724198999 is an equidigital number, since it uses as much as digits as its factorization.

78724198999 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 164602368, while the sum is 73.

The spelling of 78724198999 in words is "seventy-eight billion, seven hundred twenty-four million, one hundred ninety-eight thousand, nine hundred ninety-nine".