278816 has 12 divisors (see below), whose sum is σ = 548982. Its totient is φ = 139392.

The previous prime is 278813. The next prime is 278819. The reversal of 278816 is 618872.

278816 = T₂₃ + T₂₄ + ... + T₁₁₈.

It is an interprime number because it is at equal distance from previous prime (278813) and next prime (278819).

It can be written as a sum of positive squares in only one way, i.e., 163216 + 115600 = 404^2 + 340^2 .

It is a Harshad number since it is a multiple of its sum of digits (32), and also a Moran number because the ratio is a prime number: 8713 = 278816 / (2 + 7 + 8 + 8 + 1 + 6).

It is a d-powerful number, because it can be written as 2¹⁴ + 7 + 8² + 8⁶ + 1 + 6³ .

It is not an unprimeable number, because it can be changed into a prime (278813) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4325 + ... + 4388.

2²⁷⁸⁸¹⁶ is an apocalyptic number.

It is an amenable number.

278816 is a deficient number, since it is larger than the sum of its proper divisors (270166).

278816 is an equidigital number, since it uses as much as digits as its factorization.

278816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8723 (or 8715 counting only the distinct ones).

The product of its digits is 5376, while the sum is 32.

The square root of 278816 is about 528.0303021608. The cubic root of 278816 is about 65.3289830043.

Subtracting from 278816 its sum of digits (32), we obtain a square (278784 = 528²).

The spelling of 278816 in words is "two hundred seventy-eight thousand, eight hundred sixteen".