20163809 has 2 divisors, whose sum is σ = 20163810. Its totient is φ = 20163808.

The previous prime is 20163791. The next prime is 20163811. The reversal of 20163809 is 90836102.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13712209 + 6451600 = 3703^2 + 2540^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20163809 is a prime.

Together with 20163811, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (20163839) 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, 10081904 + 10081905.

It is an arithmetic number, because the mean of its divisors is an integer number (10081905).

Almost surely, 2^20163809 is an apocalyptic number.

It is an amenable number.

20163809 is a deficient number, since it is larger than the sum of its proper divisors (1).

20163809 is an equidigital number, since it uses as much as digits as its factorization.

20163809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2592, while the sum is 29.

The square root of 20163809 is about 4490.4130099580. The cubic root of 20163809 is about 272.1808242908.

The spelling of 20163809 in words is "twenty million, one hundred sixty-three thousand, eight hundred nine".