278945 has 8 divisors (see below), whose sum is σ = 342144. Its totient is φ = 218224.

The previous prime is 278917. The next prime is 278947. The reversal of 278945 is 549872.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 278945 - 2⁶ = 278881 is a prime.

It is a d-powerful number, because it can be written as 2¹⁸ + 7 + 9² + 8² + 4⁵ + 5⁶ .

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

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (278947) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 359 + ... + 828.

It is an arithmetic number, because the mean of its divisors is an integer number (42768).

278945 is a Friedman number, since it can be written as 7^5-8+4^9+2, using all its digits and the basic arithmetic operations.

2²⁷⁸⁹⁴⁵ is an apocalyptic number.

It is an amenable number.

278945 is a deficient number, since it is larger than the sum of its proper divisors (63199).

278945 is a wasteful number, since it uses less digits than its factorization.

278945 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1239.

The product of its digits is 20160, while the sum is 35.

The square root of 278945 is about 528.1524401155. The cubic root of 278945 is about 65.3390567201.

The spelling of 278945 in words is "two hundred seventy-eight thousand, nine hundred forty-five".