265861 has 2 divisors, whose sum is σ = 265862. Its totient is φ = 265860.

The previous prime is 265847. The next prime is 265871. The reversal of 265861 is 168562.

It is the 211-st star number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 172225 + 93636 = 415^2 + 306^2 .

It is a cyclic number.

It is not a de Polignac number, because 265861 - 2¹⁷ = 134789 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (265831) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 132930 + 132931.

It is an arithmetic number, because the mean of its divisors is an integer number (132931).

2²⁶⁵⁸⁶¹ is an apocalyptic number.

It is an amenable number.

265861 is a deficient number, since it is larger than the sum of its proper divisors (1).

265861 is an equidigital number, since it uses as much as digits as its factorization.

265861 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2880, while the sum is 28.

The square root of 265861 is about 515.6171060002. The cubic root of 265861 is about 64.3010716984.

The spelling of 265861 in words is "two hundred sixty-five thousand, eight hundred sixty-one".