18665869 has 2 divisors, whose sum is σ = 18665870. Its totient is φ = 18665868.

The previous prime is 18665851. The next prime is 18665873. The reversal of 18665869 is 96856681.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12687844 + 5978025 = 3562^2 + 2445^2 .

It is a cyclic number.

It is not a de Polignac number, because 18665869 - 2⁵ = 18665837 is a prime.

It is a super-2 number, since 2×18665869² = 696829331050322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18665819) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9332934 + 9332935.

It is an arithmetic number, because the mean of its divisors is an integer number (9332935).

Almost surely, 2^18665869 is an apocalyptic number.

It is an amenable number.

18665869 is a deficient number, since it is larger than the sum of its proper divisors (1).

18665869 is an equidigital number, since it uses as much as digits as its factorization.

18665869 is an evil number, because the sum of its binary digits is even.

The product of its digits is 622080, while the sum is 49.

The square root of 18665869 is about 4320.4014859733. The cubic root of 18665869 is about 265.2667019472.

The spelling of 18665869 in words is "eighteen million, six hundred sixty-five thousand, eight hundred sixty-nine".