865213 has 2 divisors, whose sum is σ = 865214. Its totient is φ = 865212.

The previous prime is 865211. The next prime is 865217. The reversal of 865213 is 312568.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 850084 + 15129 = 922^2 + 123^2 .

It is a cyclic number.

It is not a de Polignac number, because 865213 - 2¹ = 865211 is a prime.

Together with 865211, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (865211) 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, 432606 + 432607.

It is an arithmetic number, because the mean of its divisors is an integer number (432607).

2⁸⁶⁵²¹³ is an apocalyptic number.

It is an amenable number.

865213 is a deficient number, since it is larger than the sum of its proper divisors (1).

865213 is an equidigital number, since it uses as much as digits as its factorization.

865213 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1440, while the sum is 25.

The square root of 865213 is about 930.1682643479. The cubic root of 865213 is about 95.2886144393.

The spelling of 865213 in words is "eight hundred sixty-five thousand, two hundred thirteen".