289991 has 4 divisors (see below), whose sum is σ = 312312. Its totient is φ = 267672.

The previous prime is 289987. The next prime is 289999. The reversal of 289991 is 199982.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 199982 = 2 ⋅99991.

It is a cyclic number.

It is not a de Polignac number, because 289991 - 2² = 289987 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (289999) 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, 11141 + ... + 11166.

It is an arithmetic number, because the mean of its divisors is an integer number (78078).

2²⁸⁹⁹⁹¹ is an apocalyptic number.

289991 is a deficient number, since it is larger than the sum of its proper divisors (22321).

289991 is a wasteful number, since it uses less digits than its factorization.

289991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22320.

The product of its digits is 11664, while the sum is 38.

The square root of 289991 is about 538.5081243584. The cubic root of 289991 is about 66.1903747381.

Subtracting from 289991 its reverse (199982), we obtain a palindrome (90009).

The spelling of 289991 in words is "two hundred eighty-nine thousand, nine hundred ninety-one".