18689819 has 2 divisors, whose sum is σ = 18689820. Its totient is φ = 18689818.

The previous prime is 18689813. The next prime is 18689837. The reversal of 18689819 is 91898681.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18689819 is a prime.

It is a super-2 number, since 2×18689819² = 698618668505522, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (18689813) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9344909 + 9344910.

It is an arithmetic number, because the mean of its divisors is an integer number (9344910).

Almost surely, 2^18689819 is an apocalyptic number.

18689819 is a deficient number, since it is larger than the sum of its proper divisors (1).

18689819 is an equidigital number, since it uses as much as digits as its factorization.

18689819 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 18689819 is about 4323.1723305924. The cubic root of 18689819 is about 265.3801071903.

The spelling of 18689819 in words is "eighteen million, six hundred eighty-nine thousand, eight hundred nineteen".