18817999999 has 4 divisors (see below), whose sum is σ = 19636173936. Its totient is φ = 17999826064.

The previous prime is 18817999997. The next prime is 18818000011. The reversal of 18817999999 is 99999971881.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 99999971881 = 102499 ⋅975619.

It is a cyclic number.

It is not a de Polignac number, because 18817999999 - 2¹ = 18817999997 is a prime.

It is a Duffinian number.

18817999999 is a modest number, since divided by 999999 gives 18817 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18817999997) 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 in 3 ways as a sum of consecutive naturals, for example, 409086934 + ... + 409086979.

It is an arithmetic number, because the mean of its divisors is an integer number (4909043484).

Almost surely, 2^18817999999 is an apocalyptic number.

18817999999 is a deficient number, since it is larger than the sum of its proper divisors (818173937).

18817999999 is an equidigital number, since it uses as much as digits as its factorization.

18817999999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 818173936.

The product of its digits is 238085568, while the sum is 79.

The spelling of 18817999999 in words is "eighteen billion, eight hundred seventeen million, nine hundred ninety-nine thousand, nine hundred ninety-nine".