278549 has 2 divisors, whose sum is σ = 278550. Its totient is φ = 278548.

The previous prime is 278543. The next prime is 278557. The reversal of 278549 is 945872.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 232324 + 46225 = 482^2 + 215^2 .

It is a cyclic number.

It is not a de Polignac number, because 278549 - 2¹² = 274453 is a prime.

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

It is a plaindrome in base 15.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (278543) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 139274 + 139275.

It is an arithmetic number, because the mean of its divisors is an integer number (139275).

2²⁷⁸⁵⁴⁹ is an apocalyptic number.

It is an amenable number.

278549 is a deficient number, since it is larger than the sum of its proper divisors (1).

278549 is an equidigital number, since it uses as much as digits as its factorization.

278549 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 20160, while the sum is 35.

The square root of 278549 is about 527.7774152046. Note that the first 3 decimals coincide. The cubic root of 278549 is about 65.3081228800.

The spelling of 278549 in words is "two hundred seventy-eight thousand, five hundred forty-nine".