65809 has 2 divisors, whose sum is σ = 65810. Its totient is φ = 65808.

The previous prime is 65789. The next prime is 65827. The reversal of 65809 is 90856.

65809 is an esthetic number in base 12, because in such base its adjacent digits differ by 1.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 65025 + 784 = 255^2 + 28^2 .

It is a cyclic number.

It is not a de Polignac number, because 65809 - 2⁵ = 65777 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (65839) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32904 + 32905.

It is an arithmetic number, because the mean of its divisors is an integer number (32905).

2⁶⁵⁸⁰⁹ is an apocalyptic number.

It is an amenable number.

65809 is a deficient number, since it is larger than the sum of its proper divisors (1).

65809 is an equidigital number, since it uses as much as digits as its factorization.

65809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2160, while the sum is 28.

The square root of 65809 is about 256.5326489942. The cubic root of 65809 is about 40.3733788612.

The spelling of 65809 in words is "sixty-five thousand, eight hundred nine".