18021199 has 8 divisors (see below), whose sum is σ = 21260288. Its totient is φ = 14948280.

The previous prime is 18021197. The next prime is 18021217. The reversal of 18021199 is 99112081.

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

It is a cyclic number.

It is not a de Polignac number, because 18021199 - 2¹ = 18021197 is a prime.

It is a super-2 number, since 2×18021199² = 649527226795202, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (31).

It is a self number, because there is not a number n which added to its sum of digits gives 18021199.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18021193) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 41307 + ... + 41740.

It is an arithmetic number, because the mean of its divisors is an integer number (2657536).

Almost surely, 2^18021199 is an apocalyptic number.

18021199 is a deficient number, since it is larger than the sum of its proper divisors (3239089).

18021199 is an equidigital number, since it uses as much as digits as its factorization.

18021199 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 83085.

The product of its (nonzero) digits is 1296, while the sum is 31.

The square root of 18021199 is about 4245.1382780776. The cubic root of 18021199 is about 262.1769825705.

The spelling of 18021199 in words is "eighteen million, twenty-one thousand, one hundred ninety-nine".