18679993 has 2 divisors, whose sum is σ = 18679994. Its totient is φ = 18679992.

The previous prime is 18679987. The next prime is 18680003. The reversal of 18679993 is 39997681.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15429184 + 3250809 = 3928^2 + 1803^2 .

It is a cyclic number.

It is not a de Polignac number, because 18679993 - 2⁵ = 18679961 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 18679993.

It is not a weakly prime, because it can be changed into another prime (18679093) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9339996 + 9339997.

It is an arithmetic number, because the mean of its divisors is an integer number (9339997).

Almost surely, 2^18679993 is an apocalyptic number.

It is an amenable number.

18679993 is a deficient number, since it is larger than the sum of its proper divisors (1).

18679993 is an equidigital number, since it uses as much as digits as its factorization.

18679993 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 734832, while the sum is 52.

The square root of 18679993 is about 4322.0357471914. The cubic root of 18679993 is about 265.3335919896. Note that the first 3 decimals are identical.

The spelling of 18679993 in words is "eighteen million, six hundred seventy-nine thousand, nine hundred ninety-three".