18218999 has 4 divisors (see below), whose sum is σ = 18330936. Its totient is φ = 18107064.

The previous prime is 18218983. The next prime is 18219001. The reversal of 18218999 is 99981281.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 99981281 = 7001 ⋅14281.

It is a cyclic number.

It is not a de Polignac number, because 18218999 - 2⁴ = 18218983 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18218399) 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, 55724 + ... + 56049.

It is an arithmetic number, because the mean of its divisors is an integer number (4582734).

Almost surely, 2^18218999 is an apocalyptic number.

18218999 is a deficient number, since it is larger than the sum of its proper divisors (111937).

18218999 is a wasteful number, since it uses less digits than its factorization.

18218999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 111936.

The product of its digits is 93312, while the sum is 47.

The square root of 18218999 is about 4268.3719378705. The cubic root of 18218999 is about 263.1327092676.

The spelling of 18218999 in words is "eighteen million, two hundred eighteen thousand, nine hundred ninety-nine".