18749993 has 2 divisors, whose sum is σ = 18749994. Its totient is φ = 18749992.

The previous prime is 18749959. The next prime is 18750001. The reversal of 18749993 is 39994781.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16908544 + 1841449 = 4112^2 + 1357^2 .

It is a cyclic number.

It is not a de Polignac number, because 18749993 - 2⁸ = 18749737 is a prime.

It is not a weakly prime, because it can be changed into another prime (18749933) 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, 9374996 + 9374997.

It is an arithmetic number, because the mean of its divisors is an integer number (9374997).

Almost surely, 2^18749993 is an apocalyptic number.

It is an amenable number.

18749993 is a deficient number, since it is larger than the sum of its proper divisors (1).

18749993 is an equidigital number, since it uses as much as digits as its factorization.

18749993 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 489888, while the sum is 50.

The square root of 18749993 is about 4330.1262106317. The cubic root of 18749993 is about 265.6646092352.

The spelling of 18749993 in words is "eighteen million, seven hundred forty-nine thousand, nine hundred ninety-three".