278555 has 4 divisors (see below), whose sum is σ = 334272. Its totient is φ = 222840.

The previous prime is 278549. The next prime is 278557. The reversal of 278555 is 555872.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 278555 - 2⁶ = 278491 is a prime.

It is a Duffinian number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 278555.

It is not an unprimeable number, because it can be changed into a prime (278557) 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, 27851 + ... + 27860.

It is an arithmetic number, because the mean of its divisors is an integer number (83568).

2²⁷⁸⁵⁵⁵ is an apocalyptic number.

278555 is a deficient number, since it is larger than the sum of its proper divisors (55717).

278555 is an equidigital number, since it uses as much as digits as its factorization.

278555 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55716.

The product of its digits is 14000, while the sum is 32.

The square root of 278555 is about 527.7830993884. The cubic root of 278555 is about 65.3085917932.

It can be divided in two parts, 278 and 555, that multiplied together give a triangular number (154290 = T₅₅₅).

The spelling of 278555 in words is "two hundred seventy-eight thousand, five hundred fifty-five".