18665849 has 2 divisors, whose sum is σ = 18665850. Its totient is φ = 18665848.

The previous prime is 18665837. The next prime is 18665851. The reversal of 18665849 is 94856681.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18550249 + 115600 = 4307^2 + 340^2 .

It is a cyclic number.

It is not a de Polignac number, because 18665849 - 2⁴ = 18665833 is a prime.

Together with 18665851, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (18665819) 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, 9332924 + 9332925.

It is an arithmetic number, because the mean of its divisors is an integer number (9332925).

Almost surely, 2^18665849 is an apocalyptic number.

It is an amenable number.

18665849 is a deficient number, since it is larger than the sum of its proper divisors (1).

18665849 is an equidigital number, since it uses as much as digits as its factorization.

18665849 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 414720, while the sum is 47.

The square root of 18665849 is about 4320.3991713729. The cubic root of 18665849 is about 265.2666072051.

The spelling of 18665849 in words is "eighteen million, six hundred sixty-five thousand, eight hundred forty-nine".