18918869 has 2 divisors, whose sum is σ = 18918870. Its totient is φ = 18918868.

The previous prime is 18918859. The next prime is 18918871. The reversal of 18918869 is 96881981.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16851025 + 2067844 = 4105^2 + 1438^2 .

It is a cyclic number.

It is not a de Polignac number, because 18918869 - 2¹⁶ = 18853333 is a prime.

It is a super-2 number, since 2×18918869² = 715847208478322, which contains 22 as substring.

Together with 18918871, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18918829) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9459434 + 9459435.

It is an arithmetic number, because the mean of its divisors is an integer number (9459435).

Almost surely, 2^18918869 is an apocalyptic number.

It is an amenable number.

18918869 is a deficient number, since it is larger than the sum of its proper divisors (1).

18918869 is an equidigital number, since it uses as much as digits as its factorization.

18918869 is an evil number, because the sum of its binary digits is even.

The product of its digits is 248832, while the sum is 50.

The square root of 18918869 is about 4349.5826236548. The cubic root of 18918869 is about 266.4598158045.

The spelling of 18918869 in words is "eighteen million, nine hundred eighteen thousand, eight hundred sixty-nine".