18263989 has 2 divisors, whose sum is σ = 18263990. Its totient is φ = 18263988.

The previous prime is 18263963. The next prime is 18264017. The reversal of 18263989 is 98936281.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14691889 + 3572100 = 3833^2 + 1890^2 .

It is a cyclic number.

It is not a de Polignac number, because 18263989 - 2¹⁵ = 18231221 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18263689) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9131994 + 9131995.

It is an arithmetic number, because the mean of its divisors is an integer number (9131995).

Almost surely, 2^18263989 is an apocalyptic number.

It is an amenable number.

18263989 is a deficient number, since it is larger than the sum of its proper divisors (1).

18263989 is an equidigital number, since it uses as much as digits as its factorization.

18263989 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 186624, while the sum is 46.

The square root of 18263989 is about 4273.6388476332. The cubic root of 18263989 is about 263.3491245493.

The spelling of 18263989 in words is "eighteen million, two hundred sixty-three thousand, nine hundred eighty-nine".