291565 has 4 divisors (see below), whose sum is σ = 349884. Its totient is φ = 233248.

The previous prime is 291563. The next prime is 291569. The reversal of 291565 is 565192.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 157609 + 133956 = 397^2 + 366^2 .

It is a cyclic number.

It is not a de Polignac number, because 291565 - 2¹ = 291563 is a prime.

It is a Duffinian number.

291565 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (291563) 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 in 3 ways as a sum of consecutive naturals, for example, 29152 + ... + 29161.

It is an arithmetic number, because the mean of its divisors is an integer number (87471).

2²⁹¹⁵⁶⁵ is an apocalyptic number.

It is an amenable number.

291565 is a deficient number, since it is larger than the sum of its proper divisors (58319).

291565 is an equidigital number, since it uses as much as digits as its factorization.

291565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 58318.

The product of its digits is 2700, while the sum is 28.

The square root of 291565 is about 539.9675916201. The cubic root of 291565 is about 66.3099137603.

It can be divided in two parts, 29156 and 5, that added together give a triangular number (29161 = T₂₄₁).

The spelling of 291565 in words is "two hundred ninety-one thousand, five hundred sixty-five".