18505789 has 2 divisors, whose sum is σ = 18505790. Its totient is φ = 18505788.

The previous prime is 18505783. The next prime is 18505793. The reversal of 18505789 is 98750581.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17994564 + 511225 = 4242^2 + 715^2 .

It is a cyclic number.

It is not a de Polignac number, because 18505789 - 2¹¹ = 18503741 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18505783) 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, 9252894 + 9252895.

It is an arithmetic number, because the mean of its divisors is an integer number (9252895).

Almost surely, 2^18505789 is an apocalyptic number.

It is an amenable number.

18505789 is a deficient number, since it is larger than the sum of its proper divisors (1).

18505789 is an equidigital number, since it uses as much as digits as its factorization.

18505789 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 100800, while the sum is 43.

The square root of 18505789 is about 4301.8355384649. The cubic root of 18505789 is about 264.5062075461.

The spelling of 18505789 in words is "eighteen million, five hundred five thousand, seven hundred eighty-nine".