278421 has 24 divisors (see below), whose sum is σ = 446880. Its totient is φ = 153120.

The previous prime is 278413. The next prime is 278437. The reversal of 278421 is 124872.

It is not a de Polignac number, because 278421 - 2³ = 278413 is a prime.

278421 is a lucky number.

It is a nialpdrome in base 13.

It is a junction number, because it is equal to n+sod(n) for n = 278391 and 278400.

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 278421.

It is not an unprimeable number, because it can be changed into a prime (278491) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4690 + ... + 4748.

It is an arithmetic number, because the mean of its divisors is an integer number (18620).

2²⁷⁸⁴²¹ is an apocalyptic number.

It is an amenable number.

278421 is a deficient number, since it is larger than the sum of its proper divisors (168459).

278421 is a wasteful number, since it uses less digits than its factorization.

278421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 97 (or 86 counting only the distinct ones).

The product of its digits is 896, while the sum is 24.

The square root of 278421 is about 527.6561380293. The cubic root of 278421 is about 65.2981177935.

It can be divided in two parts, 27 and 8421, that added together give a palindrome (8448).

The spelling of 278421 in words is "two hundred seventy-eight thousand, four hundred twenty-one".