291085 has 4 divisors (see below), whose sum is σ = 349308. Its totient is φ = 232864.

The previous prime is 291077. The next prime is 291089. The reversal of 291085 is 580192.

291085 = 381² + 382².

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 145924 + 145161 = 382^2 + 381^2 .

It is a cyclic number.

It is not a de Polignac number, because 291085 - 2³ = 291077 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (291089) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 29104 + ... + 29113.

It is an arithmetic number, because the mean of its divisors is an integer number (87327).

2²⁹¹⁰⁸⁵ is an apocalyptic number.

291085 is the 382-nd centered square number.

It is an amenable number.

291085 is a deficient number, since it is larger than the sum of its proper divisors (58223).

291085 is an equidigital number, since it uses as much as digits as its factorization.

291085 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58222.

The product of its (nonzero) digits is 720, while the sum is 25.

The square root of 291085 is about 539.5229374179. The cubic root of 291085 is about 66.2735053653.

The spelling of 291085 in words is "two hundred ninety-one thousand, eighty-five".