18159989 has 2 divisors, whose sum is σ = 18159990. Its totient is φ = 18159988.

The previous prime is 18159959. The next prime is 18160013. The reversal of 18159989 is 98995181.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14326225 + 3833764 = 3785^2 + 1958^2 .

It is an emirp because it is prime and its reverse (98995181) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18159989 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18159959) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9079994 + 9079995.

It is an arithmetic number, because the mean of its divisors is an integer number (9079995).

Almost surely, 2^18159989 is an apocalyptic number.

It is an amenable number.

18159989 is a deficient number, since it is larger than the sum of its proper divisors (1).

18159989 is an equidigital number, since it uses as much as digits as its factorization.

18159989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 233280, while the sum is 50.

The square root of 18159989 is about 4261.4538598934. The cubic root of 18159989 is about 262.8483128251.

The spelling of 18159989 in words is "eighteen million, one hundred fifty-nine thousand, nine hundred eighty-nine".