18939859 has 2 divisors, whose sum is σ = 18939860. Its totient is φ = 18939858.

The previous prime is 18939857. The next prime is 18939863. The reversal of 18939859 is 95893981.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 18939859 - 2¹ = 18939857 is a prime.

Together with 18939857, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (18939857) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9469929 + 9469930.

It is an arithmetic number, because the mean of its divisors is an integer number (9469930).

Almost surely, 2^18939859 is an apocalyptic number.

18939859 is a deficient number, since it is larger than the sum of its proper divisors (1).

18939859 is an equidigital number, since it uses as much as digits as its factorization.

18939859 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 699840, while the sum is 52.

The square root of 18939859 is about 4351.9948299602. The cubic root of 18939859 is about 266.5583228273.

The spelling of 18939859 in words is "eighteen million, nine hundred thirty-nine thousand, eight hundred fifty-nine".