278381 has 4 divisors (see below), whose sum is σ = 284352. Its totient is φ = 272412.

The previous prime is 278363. The next prime is 278387. The reversal of 278381 is 183872.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a de Polignac number, because none of the positive numbers 2^k-278381 is a prime.

It is a super-2 number, since 2×278381² = 154991962322, which contains 22 as substring.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 278381.

It is not an unprimeable number, because it can be changed into a prime (278387) 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, 2915 + ... + 3008.

It is an arithmetic number, because the mean of its divisors is an integer number (71088).

2²⁷⁸³⁸¹ is an apocalyptic number.

It is an amenable number.

278381 is a deficient number, since it is larger than the sum of its proper divisors (5971).

278381 is an equidigital number, since it uses as much as digits as its factorization.

278381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5970.

The product of its digits is 2688, while the sum is 29.

The square root of 278381 is about 527.6182331952. The cubic root of 278381 is about 65.2949905751.

The spelling of 278381 in words is "two hundred seventy-eight thousand, three hundred eighty-one".