20205389 has 2 divisors, whose sum is σ = 20205390. Its totient is φ = 20205388.

The previous prime is 20205377. The next prime is 20205467. The reversal of 20205389 is 98350202.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18361225 + 1844164 = 4285^2 + 1358^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20205389 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20205329) 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, 10102694 + 10102695.

It is an arithmetic number, because the mean of its divisors is an integer number (10102695).

Almost surely, 2^20205389 is an apocalyptic number.

It is an amenable number.

20205389 is a deficient number, since it is larger than the sum of its proper divisors (1).

20205389 is an equidigital number, since it uses as much as digits as its factorization.

20205389 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4320, while the sum is 29.

The square root of 20205389 is about 4495.0404892503. The cubic root of 20205389 is about 272.3677848069.

The spelling of 20205389 in words is "twenty million, two hundred five thousand, three hundred eighty-nine".