18199381 has 2 divisors, whose sum is σ = 18199382. Its totient is φ = 18199380.

The previous prime is 18199361. The next prime is 18199421. The reversal of 18199381 is 18399181.

It is a happy number.

It is an a-pointer prime, because the next prime (18199421) can be obtained adding 18199381 to its sum of digits (40).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18198756 + 625 = 4266^2 + 25^2 .

It is an emirp because it is prime and its reverse (18399181) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18199381 - 2¹⁵ = 18166613 is a prime.

It is a super-2 number, since 2×18199381² = 662434937566322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18199331) 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 as a sum of consecutive naturals, namely, 9099690 + 9099691.

It is an arithmetic number, because the mean of its divisors is an integer number (9099691).

Almost surely, 2^18199381 is an apocalyptic number.

It is an amenable number.

18199381 is a deficient number, since it is larger than the sum of its proper divisors (1).

18199381 is an equidigital number, since it uses as much as digits as its factorization.

18199381 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 15552, while the sum is 40.

The square root of 18199381 is about 4266.0732530045. The cubic root of 18199381 is about 263.0382292975.

The spelling of 18199381 in words is "eighteen million, one hundred ninety-nine thousand, three hundred eighty-one".