18240997 has 2 divisors, whose sum is σ = 18240998. Its totient is φ = 18240996.

The previous prime is 18240979. The next prime is 18241031. The reversal of 18240997 is 79904281.

Together with previous prime (18240979) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16638241 + 1602756 = 4079^2 + 1266^2 .

It is an emirp because it is prime and its reverse (79904281) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18240997 - 2⁷ = 18240869 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18240907) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9120498 + 9120499.

It is an arithmetic number, because the mean of its divisors is an integer number (9120499).

Almost surely, 2^18240997 is an apocalyptic number.

It is an amenable number.

18240997 is a deficient number, since it is larger than the sum of its proper divisors (1).

18240997 is an equidigital number, since it uses as much as digits as its factorization.

18240997 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 36288, while the sum is 40.

The square root of 18240997 is about 4270.9480212243. The cubic root of 18240997 is about 263.2385706493.

The spelling of 18240997 in words is "eighteen million, two hundred forty thousand, nine hundred ninety-seven".