18663109 has 2 divisors, whose sum is σ = 18663110. Its totient is φ = 18663108.

The previous prime is 18663103. The next prime is 18663119. The reversal of 18663109 is 90136681.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11356900 + 7306209 = 3370^2 + 2703^2 .

It is an emirp because it is prime and its reverse (90136681) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18663109 - 2⁷ = 18662981 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18663103) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9331554 + 9331555.

It is an arithmetic number, because the mean of its divisors is an integer number (9331555).

Almost surely, 2^18663109 is an apocalyptic number.

It is an amenable number.

18663109 is a deficient number, since it is larger than the sum of its proper divisors (1).

18663109 is an equidigital number, since it uses as much as digits as its factorization.

18663109 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7776, while the sum is 34.

The square root of 18663109 is about 4320.0820594058. The cubic root of 18663109 is about 265.2536268852.

The spelling of 18663109 in words is "eighteen million, six hundred sixty-three thousand, one hundred nine".