18999993 has 8 divisors (see below), whose sum is σ = 26150656. Its totient is φ = 12258000.

The previous prime is 18999991. The next prime is 18999997. The reversal of 18999993 is 39999981.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 18999993 - 2¹ = 18999991 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (18999991) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 102058 + ... + 102243.

It is an arithmetic number, because the mean of its divisors is an integer number (3268832).

Almost surely, 2^18999993 is an apocalyptic number.

It is an amenable number.

18999993 is a deficient number, since it is larger than the sum of its proper divisors (7150663).

18999993 is a wasteful number, since it uses less digits than its factorization.

18999993 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 204335.

The product of its digits is 1417176, while the sum is 57.

The square root of 18999993 is about 4358.8981405855. The cubic root of 18999993 is about 266.8401321023.

The spelling of 18999993 in words is "eighteen million, nine hundred ninety-nine thousand, nine hundred ninety-three".