18820897 has 2 divisors, whose sum is σ = 18820898. Its totient is φ = 18820896.

The previous prime is 18820891. The next prime is 18820909. The reversal of 18820897 is 79802881.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18740241 + 80656 = 4329^2 + 284^2 .

It is an emirp because it is prime and its reverse (79802881) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18820897 - 2³ = 18820889 is a prime.

It is not a weakly prime, because it can be changed into another prime (18820891) 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, 9410448 + 9410449.

It is an arithmetic number, because the mean of its divisors is an integer number (9410449).

Almost surely, 2^18820897 is an apocalyptic number.

It is an amenable number.

18820897 is a deficient number, since it is larger than the sum of its proper divisors (1).

18820897 is an equidigital number, since it uses as much as digits as its factorization.

18820897 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 64512, while the sum is 43.

The square root of 18820897 is about 4338.3057752998. The cubic root of 18820897 is about 265.9990625026. Note that the first 3 decimals are identical.

The spelling of 18820897 in words is "eighteen million, eight hundred twenty thousand, eight hundred ninety-seven".