278638 has 8 divisors (see below), whose sum is σ = 421632. Its totient is φ = 138096.

The previous prime is 278627. The next prime is 278639. The reversal of 278638 is 836872.

It is a happy number.

278638 is nontrivially palindromic in base 13.

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

It is a d-powerful number, because it can be written as 2¹⁴ + 7 + 6² + 8² + 3 + 8⁶ .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (278639) by changing a digit.

278638 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

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 3 ways as a sum of consecutive naturals, for example, 295 + ... + 802.

It is an arithmetic number, because the mean of its divisors is an integer number (52704).

2²⁷⁸⁶³⁸ is an apocalyptic number.

278638 is a deficient number, since it is larger than the sum of its proper divisors (142994).

278638 is a wasteful number, since it uses less digits than its factorization.

278638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1226.

The product of its digits is 16128, while the sum is 34.

The square root of 278638 is about 527.8617243180. The cubic root of 278638 is about 65.3150777353.

The spelling of 278638 in words is "two hundred seventy-eight thousand, six hundred thirty-eight".