18493997 has 2 divisors, whose sum is σ = 18493998. Its totient is φ = 18493996.

The previous prime is 18493991. The next prime is 18494033. The reversal of 18493997 is 79939481.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10118761 + 8375236 = 3181^2 + 2894^2 .

It is an emirp because it is prime and its reverse (79939481) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18493997 - 2¹⁰ = 18492973 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18493991) 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, 9246998 + 9246999.

It is an arithmetic number, because the mean of its divisors is an integer number (9246999).

Almost surely, 2^18493997 is an apocalyptic number.

It is an amenable number.

18493997 is a deficient number, since it is larger than the sum of its proper divisors (1).

18493997 is an equidigital number, since it uses as much as digits as its factorization.

18493997 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 489888, while the sum is 50.

The square root of 18493997 is about 4300.4647423273. The cubic root of 18493997 is about 264.4500139602.

The spelling of 18493997 in words is "eighteen million, four hundred ninety-three thousand, nine hundred ninety-seven".