18417321997 has 2 divisors, whose sum is σ = 18417321998. Its totient is φ = 18417321996.

The previous prime is 18417321947. The next prime is 18417322031. The reversal of 18417321997 is 79912371481.

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., 17834534116 + 582787881 = 133546^2 + 24141^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18417321997 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18417321917) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9208660998 + 9208660999.

It is an arithmetic number, because the mean of its divisors is an integer number (9208660999).

Almost surely, 2^18417321997 is an apocalyptic number.

It is an amenable number.

18417321997 is a deficient number, since it is larger than the sum of its proper divisors (1).

18417321997 is an equidigital number, since it uses as much as digits as its factorization.

18417321997 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 762048, while the sum is 52.

The spelling of 18417321997 in words is "eighteen billion, four hundred seventeen million, three hundred twenty-one thousand, nine hundred ninety-seven".