278649 has 12 divisors (see below), whose sum is σ = 460096. Its totient is φ = 159192.

The previous prime is 278639. The next prime is 278651. The reversal of 278649 is 946872.

278649 is a `hidden beast` number, since 2 + 7 + 8 + 649 = 666.

It is not a de Polignac number, because 278649 - 2⁵ = 278617 is a prime.

It is not an unprimeable number, because it can be changed into a prime (278609) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2149 + ... + 2274.

278649 is a Friedman number, since it can be written as 9+6^7-(8-2)^4, using all its digits and the basic arithmetic operations.

2²⁷⁸⁶⁴⁹ is an apocalyptic number.

It is an amenable number.

278649 is a deficient number, since it is larger than the sum of its proper divisors (181447).

278649 is a wasteful number, since it uses less digits than its factorization.

278649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4436 (or 4433 counting only the distinct ones).

The product of its digits is 24192, while the sum is 36.

The square root of 278649 is about 527.8721436106. The cubic root of 278649 is about 65.3159372213.

The spelling of 278649 in words is "two hundred seventy-eight thousand, six hundred forty-nine".