20673209 has 2 divisors, whose sum is σ = 20673210. Its totient is φ = 20673208.

The previous prime is 20673203. The next prime is 20673217. The reversal of 20673209 is 90237602.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12816400 + 7856809 = 3580^2 + 2803^2 .

It is a cyclic number.

It is not a de Polignac number, because 20673209 - 2⁴ = 20673193 is a prime.

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 (20673203) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10336604 + 10336605.

It is an arithmetic number, because the mean of its divisors is an integer number (10336605).

Almost surely, 2^20673209 is an apocalyptic number.

It is an amenable number.

20673209 is a deficient number, since it is larger than the sum of its proper divisors (1).

20673209 is an equidigital number, since it uses as much as digits as its factorization.

20673209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4536, while the sum is 29.

The square root of 20673209 is about 4546.7800694557. The cubic root of 20673209 is about 274.4538316940.

The spelling of 20673209 in words is "twenty million, six hundred seventy-three thousand, two hundred nine".