20331209 has 2 divisors, whose sum is σ = 20331210. Its totient is φ = 20331208.

The previous prime is 20331191. The next prime is 20331253. The reversal of 20331209 is 90213302.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15578809 + 4752400 = 3947^2 + 2180^2 .

It is a cyclic number.

It is not a de Polignac number, because 20331209 - 2⁸ = 20330953 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (20331109) 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, 10165604 + 10165605.

It is an arithmetic number, because the mean of its divisors is an integer number (10165605).

Almost surely, 2^20331209 is an apocalyptic number.

It is an amenable number.

20331209 is a deficient number, since it is larger than the sum of its proper divisors (1).

20331209 is an equidigital number, since it uses as much as digits as its factorization.

20331209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 324, while the sum is 20.

The square root of 20331209 is about 4509.0141938122. The cubic root of 20331209 is about 272.9319647803.

The spelling of 20331209 in words is "twenty million, three hundred thirty-one thousand, two hundred nine".