18418591 has 2 divisors, whose sum is σ = 18418592. Its totient is φ = 18418590.

The previous prime is 18418583. The next prime is 18418627. The reversal of 18418591 is 19581481.

It is a weak prime.

It is an emirp because it is prime and its reverse (19581481) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18418591 - 2³ = 18418583 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 18418591.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18418571) 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, 9209295 + 9209296.

It is an arithmetic number, because the mean of its divisors is an integer number (9209296).

Almost surely, 2^18418591 is an apocalyptic number.

18418591 is a deficient number, since it is larger than the sum of its proper divisors (1).

18418591 is an equidigital number, since it uses as much as digits as its factorization.

18418591 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 11520, while the sum is 37.

The square root of 18418591 is about 4291.6885954132. The cubic root of 18418591 is about 264.0901083210.

It can be divided in two parts, 18 and 418591, that added together give a square (418609 = 647²).

The spelling of 18418591 in words is "eighteen million, four hundred eighteen thousand, five hundred ninety-one".