278989 has 4 divisors (see below), whose sum is σ = 280924. Its totient is φ = 277056.

The previous prime is 278981. The next prime is 279001. The reversal of 278989 is 989872.

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 110889 + 168100 = 333^2 + 410^2 .

It is a cyclic number.

It is not a de Polignac number, because 278989 - 2³ = 278981 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (278981) 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, 732 + ... + 1045.

It is an arithmetic number, because the mean of its divisors is an integer number (70231).

2²⁷⁸⁹⁸⁹ is an apocalyptic number.

It is an amenable number.

278989 is a deficient number, since it is larger than the sum of its proper divisors (1935).

278989 is a wasteful number, since it uses less digits than its factorization.

278989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1934.

The product of its digits is 72576, while the sum is 43.

The square root of 278989 is about 528.1940931135. The cubic root of 278989 is about 65.3424920059.

The spelling of 278989 in words is "two hundred seventy-eight thousand, nine hundred eighty-nine".