18997273 has 2 divisors, whose sum is σ = 18997274. Its totient is φ = 18997272.

The previous prime is 18997249. The next prime is 18997331. The reversal of 18997273 is 37279981.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15264649 + 3732624 = 3907^2 + 1932^2 .

It is an emirp because it is prime and its reverse (37279981) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18997273 is a prime.

It is not a weakly prime, because it can be changed into another prime (18997213) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9498636 + 9498637.

It is an arithmetic number, because the mean of its divisors is an integer number (9498637).

Almost surely, 2^18997273 is an apocalyptic number.

It is an amenable number.

18997273 is a deficient number, since it is larger than the sum of its proper divisors (1).

18997273 is an equidigital number, since it uses as much as digits as its factorization.

18997273 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 190512, while the sum is 46.

The square root of 18997273 is about 4358.5861239627. The cubic root of 18997273 is about 266.8273980661.

The spelling of 18997273 in words is "eighteen million, nine hundred ninety-seven thousand, two hundred seventy-three".