320861 has 2 divisors, whose sum is σ = 320862. Its totient is φ = 320860.

The previous prime is 320851. The next prime is 320867. The reversal of 320861 is 168023.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 164836 + 156025 = 406^2 + 395^2 .

It is an emirp because it is prime and its reverse (168023) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 320861 - 2¹⁴ = 304477 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (320867) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 160430 + 160431.

It is an arithmetic number, because the mean of its divisors is an integer number (160431).

2³²⁰⁸⁶¹ is an apocalyptic number.

It is an amenable number.

320861 is a deficient number, since it is larger than the sum of its proper divisors (1).

320861 is an equidigital number, since it uses as much as digits as its factorization.

320861 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 288, while the sum is 20.

The square root of 320861 is about 566.4459374027. The cubic root of 320861 is about 68.4603283171.

Adding to 320861 its reverse (168023), we get a palindrome (488884).

The spelling of 320861 in words is "three hundred twenty thousand, eight hundred sixty-one".