866213 has 2 divisors, whose sum is σ = 866214. Its totient is φ = 866212.

The previous prime is 866197. The next prime is 866221. The reversal of 866213 is 312668.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 850084 + 16129 = 922^2 + 127^2 .

It is a cyclic number.

It is not a de Polignac number, because 866213 - 2⁴ = 866197 is a prime.

It is a super-2 number, since 2×866213² = 1500649922738, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (866293) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 433106 + 433107.

It is an arithmetic number, because the mean of its divisors is an integer number (433107).

2⁸⁶⁶²¹³ is an apocalyptic number.

It is an amenable number.

866213 is a deficient number, since it is larger than the sum of its proper divisors (1).

866213 is an equidigital number, since it uses as much as digits as its factorization.

866213 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1728, while the sum is 26.

The square root of 866213 is about 930.7056462706. The cubic root of 866213 is about 95.3253113479.

The spelling of 866213 in words is "eight hundred sixty-six thousand, two hundred thirteen".