18825809 has 2 divisors, whose sum is σ = 18825810. Its totient is φ = 18825808.

The previous prime is 18825797. The next prime is 18825823. The reversal of 18825809 is 90852881.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15484225 + 3341584 = 3935^2 + 1828^2 .

It is a cyclic number.

It is not a de Polignac number, because 18825809 - 2²⁴ = 2048593 is a prime.

It is a super-2 number, since 2×18825809² = 708822169008962, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (18825839) 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, 9412904 + 9412905.

It is an arithmetic number, because the mean of its divisors is an integer number (9412905).

Almost surely, 2^18825809 is an apocalyptic number.

It is an amenable number.

18825809 is a deficient number, since it is larger than the sum of its proper divisors (1).

18825809 is an equidigital number, since it uses as much as digits as its factorization.

18825809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 46080, while the sum is 41.

The square root of 18825809 is about 4338.8718579834. The cubic root of 18825809 is about 266.0222012110.

The spelling of 18825809 in words is "eighteen million, eight hundred twenty-five thousand, eight hundred nine".