18540989 has 2 divisors, whose sum is σ = 18540990. Its totient is φ = 18540988.

The previous prime is 18540971. The next prime is 18540997. The reversal of 18540989 is 98904581.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14707225 + 3833764 = 3835^2 + 1958^2 .

It is a cyclic number.

It is not a de Polignac number, because 18540989 - 2¹⁶ = 18475453 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18540689) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9270494 + 9270495.

It is an arithmetic number, because the mean of its divisors is an integer number (9270495).

Almost surely, 2^18540989 is an apocalyptic number.

It is an amenable number.

18540989 is a deficient number, since it is larger than the sum of its proper divisors (1).

18540989 is an equidigital number, since it uses as much as digits as its factorization.

18540989 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 103680, while the sum is 44.

The square root of 18540989 is about 4305.9248716159. The cubic root of 18540989 is about 264.6738077399.

The spelling of 18540989 in words is "eighteen million, five hundred forty thousand, nine hundred eighty-nine".