18659993 has 4 divisors (see below), whose sum is σ = 20356368. Its totient is φ = 16963620.

The previous prime is 18659959. The next prime is 18660011. The reversal of 18659993 is 39995681.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 39995681 = 11 ⋅3635971.

It is a cyclic number.

It is not a de Polignac number, because 18659993 - 2¹⁴ = 18643609 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18659393) 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 3 ways as a sum of consecutive naturals, for example, 848171 + ... + 848192.

It is an arithmetic number, because the mean of its divisors is an integer number (5089092).

Almost surely, 2^18659993 is an apocalyptic number.

It is an amenable number.

18659993 is a deficient number, since it is larger than the sum of its proper divisors (1696375).

18659993 is a wasteful number, since it uses less digits than its factorization.

18659993 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1696374.

The product of its digits is 524880, while the sum is 50.

The square root of 18659993 is about 4319.7214030537. The cubic root of 18659993 is about 265.2388637804.

The spelling of 18659993 in words is "eighteen million, six hundred fifty-nine thousand, nine hundred ninety-three".