278965 has 4 divisors (see below), whose sum is σ = 334764. Its totient is φ = 223168.

The previous prime is 278947. The next prime is 278981. The reversal of 278965 is 569872.

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 54289 + 224676 = 233^2 + 474^2 .

It is a cyclic number.

It is not a de Polignac number, because 278965 - 2¹¹ = 276917 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 an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 27892 + ... + 27901.

It is an arithmetic number, because the mean of its divisors is an integer number (83691).

2²⁷⁸⁹⁶⁵ is an apocalyptic number.

It is an amenable number.

278965 is a deficient number, since it is larger than the sum of its proper divisors (55799).

278965 is an equidigital number, since it uses as much as digits as its factorization.

278965 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55798.

The product of its digits is 30240, while the sum is 37.

The square root of 278965 is about 528.1713737036. The cubic root of 278965 is about 65.3406182584.

The spelling of 278965 in words is "two hundred seventy-eight thousand, nine hundred sixty-five".