18406789 has 2 divisors, whose sum is σ = 18406790. Its totient is φ = 18406788.

The previous prime is 18406783. The next prime is 18406807. The reversal of 18406789 is 98760481.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18232900 + 173889 = 4270^2 + 417^2 .

It is an emirp because it is prime and its reverse (98760481) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18406789 - 2³ = 18406781 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18406781) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9203394 + 9203395.

It is an arithmetic number, because the mean of its divisors is an integer number (9203395).

Almost surely, 2^18406789 is an apocalyptic number.

It is an amenable number.

18406789 is a deficient number, since it is larger than the sum of its proper divisors (1).

18406789 is an equidigital number, since it uses as much as digits as its factorization.

18406789 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 96768, while the sum is 43.

The square root of 18406789 is about 4290.3133918165. The cubic root of 18406789 is about 264.0336896476.

The spelling of 18406789 in words is "eighteen million, four hundred six thousand, seven hundred eighty-nine".