18556849 has 2 divisors, whose sum is σ = 18556850. Its totient is φ = 18556848.

The previous prime is 18556847. The next prime is 18556913. The reversal of 18556849 is 94865581.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17164449 + 1392400 = 4143^2 + 1180^2 .

It is an emirp because it is prime and its reverse (94865581) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18556849 - 2¹ = 18556847 is a prime.

Together with 18556847, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 18556799 and 18556808.

It is not a weakly prime, because it can be changed into another prime (18556847) 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, 9278424 + 9278425.

It is an arithmetic number, because the mean of its divisors is an integer number (9278425).

Almost surely, 2^18556849 is an apocalyptic number.

It is an amenable number.

18556849 is a deficient number, since it is larger than the sum of its proper divisors (1).

18556849 is an equidigital number, since it uses as much as digits as its factorization.

18556849 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 345600, while the sum is 46.

The square root of 18556849 is about 4307.7661264279. The cubic root of 18556849 is about 264.7492537377.

The spelling of 18556849 in words is "eighteen million, five hundred fifty-six thousand, eight hundred forty-nine".