581261 has 2 divisors, whose sum is σ = 581262. Its totient is φ = 581260.

The previous prime is 581239. The next prime is 581263. The reversal of 581261 is 162185.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 570025 + 11236 = 755^2 + 106^2 .

It is a cyclic number.

It is not a de Polignac number, because 581261 - 2⁶ = 581197 is a prime.

Together with 581263, it forms a pair of twin primes.

It is a Chen prime.

It is a plaindrome in base 11.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (581263) 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, 290630 + 290631.

It is an arithmetic number, because the mean of its divisors is an integer number (290631).

2⁵⁸¹²⁶¹ is an apocalyptic number.

It is an amenable number.

581261 is a deficient number, since it is larger than the sum of its proper divisors (1).

581261 is an equidigital number, since it uses as much as digits as its factorization.

581261 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 480, while the sum is 23.

The square root of 581261 is about 762.4047481489. The cubic root of 581261 is about 83.4559031867.

The spelling of 581261 in words is "five hundred eighty-one thousand, two hundred sixty-one".