20570909 has 2 divisors, whose sum is σ = 20570910. Its totient is φ = 20570908.

The previous prime is 20570903. The next prime is 20570917. The reversal of 20570909 is 90907502.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17455684 + 3115225 = 4178^2 + 1765^2 .

It is a cyclic number.

It is not a de Polignac number, because 20570909 - 2⁸ = 20570653 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20570903) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10285454 + 10285455.

It is an arithmetic number, because the mean of its divisors is an integer number (10285455).

Almost surely, 2^20570909 is an apocalyptic number.

It is an amenable number.

20570909 is a deficient number, since it is larger than the sum of its proper divisors (1).

20570909 is an equidigital number, since it uses as much as digits as its factorization.

20570909 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5670, while the sum is 32.

The square root of 20570909 is about 4535.5163983829. The cubic root of 20570909 is about 274.0003773948. Note that the first 3 decimals are identical.

The spelling of 20570909 in words is "twenty million, five hundred seventy thousand, nine hundred nine".