18387899 has 4 divisors (see below), whose sum is σ = 18408264. Its totient is φ = 18367536.

The previous prime is 18387883. The next prime is 18387917. The reversal of 18387899 is 99878381.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 18387899 - 2⁴ = 18387883 is a prime.

It is a super-2 number, since 2×18387899² = 676229659268402, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 18387899.

It is not an unprimeable number, because it can be changed into a prime (18387599) 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, 8762 + ... + 10655.

It is an arithmetic number, because the mean of its divisors is an integer number (4602066).

Almost surely, 2^18387899 is an apocalyptic number.

18387899 is a deficient number, since it is larger than the sum of its proper divisors (20365).

18387899 is an equidigital number, since it uses as much as digits as its factorization.

18387899 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20364.

The product of its digits is 870912, while the sum is 53.

The square root of 18387899 is about 4288.1113558302. Note that the first 3 decimals coincide. The cubic root of 18387899 is about 263.9433370510.

The spelling of 18387899 in words is "eighteen million, three hundred eighty-seven thousand, eight hundred ninety-nine".