18207997 has 2 divisors, whose sum is σ = 18207998. Its totient is φ = 18207996.

The previous prime is 18207961. The next prime is 18208007. The reversal of 18207997 is 79970281.

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., 13793796 + 4414201 = 3714^2 + 2101^2 .

It is an emirp because it is prime and its reverse (79970281) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18207997 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18207907) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9103998 + 9103999.

It is an arithmetic number, because the mean of its divisors is an integer number (9103999).

Almost surely, 2^18207997 is an apocalyptic number.

It is an amenable number.

18207997 is a deficient number, since it is larger than the sum of its proper divisors (1).

18207997 is an equidigital number, since it uses as much as digits as its factorization.

18207997 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 63504, while the sum is 43.

The square root of 18207997 is about 4267.0829614621. The cubic root of 18207997 is about 263.0797321712.

The spelling of 18207997 in words is "eighteen million, two hundred seven thousand, nine hundred ninety-seven".