865409 has 2 divisors, whose sum is σ = 865410. Its totient is φ = 865408.

The previous prime is 865379. The next prime is 865457. The reversal of 865409 is 904568.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 861184 + 4225 = 928^2 + 65^2 .

It is a cyclic number.

It is not a de Polignac number, because 865409 - 2⁸ = 865153 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (865499) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 432704 + 432705.

It is an arithmetic number, because the mean of its divisors is an integer number (432705).

2⁸⁶⁵⁴⁰⁹ is an apocalyptic number.

It is an amenable number.

865409 is a deficient number, since it is larger than the sum of its proper divisors (1).

865409 is an equidigital number, since it uses as much as digits as its factorization.

865409 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8640, while the sum is 32.

The square root of 865409 is about 930.2736156637. The cubic root of 865409 is about 95.2958092605.

The spelling of 865409 in words is "eight hundred sixty-five thousand, four hundred nine".