20765909 has 2 divisors, whose sum is σ = 20765910. Its totient is φ = 20765908.

The previous prime is 20765893. The next prime is 20765923. The reversal of 20765909 is 90956702.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20729809 + 36100 = 4553^2 + 190^2 .

It is a cyclic number.

It is not a de Polignac number, because 20765909 - 2⁴ = 20765893 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 (20765929) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10382954 + 10382955.

It is an arithmetic number, because the mean of its divisors is an integer number (10382955).

Almost surely, 2^20765909 is an apocalyptic number.

It is an amenable number.

20765909 is a deficient number, since it is larger than the sum of its proper divisors (1).

20765909 is an equidigital number, since it uses as much as digits as its factorization.

20765909 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 34020, while the sum is 38.

The square root of 20765909 is about 4556.9626946026. The cubic root of 20765909 is about 274.8634429447.

The spelling of 20765909 in words is "twenty million, seven hundred sixty-five thousand, nine hundred nine".