278641 has 8 divisors (see below), whose sum is σ = 309024. Its totient is φ = 249120.

The previous prime is 278639. The next prime is 278651. The reversal of 278641 is 146872.

It is the 216-th star number.

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

It is a cyclic number.

It is not a de Polignac number, because 278641 - 2¹ = 278639 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (278611) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 630 + ... + 976.

It is an arithmetic number, because the mean of its divisors is an integer number (38628).

278641 is a Friedman number, since it can be written as 6^7-(8-2)^4+1, using all its digits and the basic arithmetic operations.

2²⁷⁸⁶⁴¹ is an apocalyptic number.

It is an amenable number.

278641 is a deficient number, since it is larger than the sum of its proper divisors (30383).

278641 is a wasteful number, since it uses less digits than its factorization.

278641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 431.

The product of its digits is 2688, while the sum is 28.

The square root of 278641 is about 527.8645659637. The cubic root of 278641 is about 65.3153121428.

Subtracting from 278641 its reverse (146872), we obtain a square (131769 = 363²).

It can be divided in two parts, 278 and 641, that added together give a palindrome (919).

The spelling of 278641 in words is "two hundred seventy-eight thousand, six hundred forty-one".