278643240 has 192 divisors, whose sum is σ = 951350400. Its totient is φ = 73343232.

The previous prime is 278643217. The next prime is 278643241. The reversal of 278643240 is 42346872.

278643240 is a `hidden beast` number, since 2 + 7 + 8 + 643 + 2 + 4 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 278643195 and 278643204.

It is not an unprimeable number, because it can be changed into a prime (278643241) 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 47 ways as a sum of consecutive naturals, for example, 1059349 + ... + 1059611.

It is an arithmetic number, because the mean of its divisors is an integer number (4954950).

Almost surely, 2^278643240 is an apocalyptic number.

278643240 is a gapful number since it is divisible by the number (20) 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 278643240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (475675200).

278643240 is an abundant number, since it is smaller than the sum of its proper divisors (672707160).

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

278643240 is a wasteful number, since it uses less digits than its factorization.

278643240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 398 (or 382 counting only the distinct ones).

The product of its (nonzero) digits is 64512, while the sum is 36.

The square root of 278643240 is about 16692.6103411060. The cubic root of 278643240 is about 653.1548716602.

The spelling of 278643240 in words is "two hundred seventy-eight million, six hundred forty-three thousand, two hundred forty".