320500261 has 2 divisors, whose sum is σ = 320500262. Its totient is φ = 320500260.

The previous prime is 320500247. The next prime is 320500273. The reversal of 320500261 is 162005023.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 284428225 + 36072036 = 16865^2 + 6006^2 .

It is an emirp because it is prime and its reverse (162005023) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 320500261 - 2⁹ = 320499749 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 (320500231) 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, 160250130 + 160250131.

It is an arithmetic number, because the mean of its divisors is an integer number (160250131).

Almost surely, 2^320500261 is an apocalyptic number.

It is an amenable number.

320500261 is a deficient number, since it is larger than the sum of its proper divisors (1).

320500261 is an equidigital number, since it uses as much as digits as its factorization.

320500261 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 360, while the sum is 19.

The square root of 320500261 is about 17902.5210794458. The cubic root of 320500261 is about 684.3466240426.

Adding to 320500261 its reverse (162005023), we get a palindrome (482505284).

The spelling of 320500261 in words is "three hundred twenty million, five hundred thousand, two hundred sixty-one".