289981 has 4 divisors (see below), whose sum is σ = 291100. Its totient is φ = 288864.

The previous prime is 289973. The next prime is 289987. The reversal of 289981 is 189982.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 156025 + 133956 = 395^2 + 366^2 .

It is a cyclic number.

It is not a de Polignac number, because 289981 - 2³ = 289973 is a prime.

It is a super-2 number, since 2×289981² = 168177960722, which contains 22 as substring.

It is a Duffinian number.

289981 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 289981.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (289987) 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, 55 + ... + 763.

It is an arithmetic number, because the mean of its divisors is an integer number (72775).

2²⁸⁹⁹⁸¹ is an apocalyptic number.

It is an amenable number.

289981 is a deficient number, since it is larger than the sum of its proper divisors (1119).

289981 is an equidigital number, since it uses as much as digits as its factorization.

289981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1118.

The product of its digits is 10368, while the sum is 37.

The square root of 289981 is about 538.4988393674. The cubic root of 289981 is about 66.1896138968.

Subtracting from 289981 its reverse (189982), we obtain a palindrome (99999).

The spelling of 289981 in words is "two hundred eighty-nine thousand, nine hundred eighty-one".