18809393 has 2 divisors, whose sum is σ = 18809394. Its totient is φ = 18809392.

The previous prime is 18809389. The next prime is 18809419. The reversal of 18809393 is 39390881.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18421264 + 388129 = 4292^2 + 623^2 .

It is a cyclic number.

It is not a de Polignac number, because 18809393 - 2² = 18809389 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 18809393.

It is not a weakly prime, because it can be changed into another prime (18809303) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9404696 + 9404697.

It is an arithmetic number, because the mean of its divisors is an integer number (9404697).

Almost surely, 2^18809393 is an apocalyptic number.

It is an amenable number.

18809393 is a deficient number, since it is larger than the sum of its proper divisors (1).

18809393 is an equidigital number, since it uses as much as digits as its factorization.

18809393 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 46656, while the sum is 41.

The square root of 18809393 is about 4336.9797094291. The cubic root of 18809393 is about 265.9448554352.

It can be divided in two parts, 18809 and 393, that multiplied together give a palindrome (7391937).

The spelling of 18809393 in words is "eighteen million, eight hundred nine thousand, three hundred ninety-three".