865123211 has 2 divisors, whose sum is σ = 865123212. Its totient is φ = 865123210.

The previous prime is 865123199. The next prime is 865123249. The reversal of 865123211 is 112321568.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 865123211 - 2¹⁰ = 865122187 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (865123261) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 432561605 + 432561606.

It is an arithmetic number, because the mean of its divisors is an integer number (432561606).

Almost surely, 2^865123211 is an apocalyptic number.

865123211 is a deficient number, since it is larger than the sum of its proper divisors (1).

865123211 is an equidigital number, since it uses as much as digits as its factorization.

865123211 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2880, while the sum is 29.

The square root of 865123211 is about 29412.9769149605. The cubic root of 865123211 is about 952.8531807748.

Adding to 865123211 its reverse (112321568), we get a palindrome (977444779).

The spelling of 865123211 in words is "eight hundred sixty-five million, one hundred twenty-three thousand, two hundred eleven".