278478864 has 80 divisors (see below), whose sum is σ = 808430400. Its totient is φ = 91770624.

The previous prime is 278478821. The next prime is 278478899. The reversal of 278478864 is 468874872.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a self number, because there is not a number n which added to its sum of digits gives 278478864.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 34827 + ... + 42069.

It is an arithmetic number, because the mean of its divisors is an integer number (10105380).

Almost surely, 2^278478864 is an apocalyptic number.

278478864 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 278478864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (404215200).

278478864 is an abundant number, since it is smaller than the sum of its proper divisors (529951536).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

278478864 is a wasteful number, since it uses less digits than its factorization.

278478864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7349 (or 7337 counting only the distinct ones).

The product of its digits is 4816896, while the sum is 54.

The square root of 278478864 is about 16687.6859989634. The cubic root of 278478864 is about 653.0264109759.

The spelling of 278478864 in words is "two hundred seventy-eight million, four hundred seventy-eight thousand, eight hundred sixty-four".