278485 has 4 divisors (see below), whose sum is σ = 334188. Its totient is φ = 222784.

The previous prime is 278479. The next prime is 278489. The reversal of 278485 is 584872.

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 221841 + 56644 = 471^2 + 238^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-278485 is a prime.

It is a Duffinian number.

It is a plaindrome in base 13 and base 15.

It is a self number, because there is not a number n which added to its sum of digits gives 278485.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (278489) 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, 27844 + ... + 27853.

It is an arithmetic number, because the mean of its divisors is an integer number (83547).

2²⁷⁸⁴⁸⁵ is an apocalyptic number.

It is an amenable number.

278485 is a deficient number, since it is larger than the sum of its proper divisors (55703).

278485 is an equidigital number, since it uses as much as digits as its factorization.

278485 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55702.

The product of its digits is 17920, while the sum is 34.

The square root of 278485 is about 527.7167801008. The cubic root of 278485 is about 65.3031207199.

It can be divided in two parts, 2 and 78485, that added together give a palindrome (78487).

The spelling of 278485 in words is "two hundred seventy-eight thousand, four hundred eighty-five".