20320409 has 2 divisors, whose sum is σ = 20320410. Its totient is φ = 20320408.

The previous prime is 20320373. The next prime is 20320427. The reversal of 20320409 is 90402302.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12054784 + 8265625 = 3472^2 + 2875^2 .

It is a cyclic number.

It is not a de Polignac number, because 20320409 - 2¹² = 20316313 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 (20320439) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10160204 + 10160205.

It is an arithmetic number, because the mean of its divisors is an integer number (10160205).

Almost surely, 2^20320409 is an apocalyptic number.

It is an amenable number.

20320409 is a deficient number, since it is larger than the sum of its proper divisors (1).

20320409 is an equidigital number, since it uses as much as digits as its factorization.

20320409 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 432, while the sum is 20.

The square root of 20320409 is about 4507.8164337071. The cubic root of 20320409 is about 272.8836287909.

The spelling of 20320409 in words is "twenty million, three hundred twenty thousand, four hundred nine".