278778313 has 24 divisors (see below), whose sum is σ = 319392584. Its totient is φ = 242922240.

The previous prime is 278778289. The next prime is 278778337. The reversal of 278778313 is 313877872.

It is an interprime number because it is at equal distance from previous prime (278778289) and next prime (278778337).

It can be written as a sum of positive squares in 4 ways, for example, as 38900169 + 239878144 = 6237^2 + 15488^2 .

It is not a de Polignac number, because 278778313 - 2⁹ = 278777801 is a prime.

It is a super-3 number, since 3×278778313³ (a number of 26 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (278778343) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 326395 + ... + 327247.

Almost surely, 2^278778313 is an apocalyptic number.

It is an amenable number.

278778313 is a deficient number, since it is larger than the sum of its proper divisors (40614271).

278778313 is a wasteful number, since it uses less digits than its factorization.

278778313 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 985 (or 974 counting only the distinct ones).

The product of its digits is 395136, while the sum is 46.

The square root of 278778313 is about 16696.6557429924. The cubic root of 278778313 is about 653.2603940913.

The spelling of 278778313 in words is "two hundred seventy-eight million, seven hundred seventy-eight thousand, three hundred thirteen".