278661220 has 48 divisors (see below), whose sum is σ = 617480640. Its totient is φ = 105342336.

The previous prime is 278661217. The next prime is 278661233. The reversal of 278661220 is 22166872.

278661220 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 247579 + ... + 248701.

It is an arithmetic number, because the mean of its divisors is an integer number (12864180).

Almost surely, 2^278661220 is an apocalyptic number.

278661220 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 278661220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (308740320).

278661220 is an abundant number, since it is smaller than the sum of its proper divisors (338819420).

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

278661220 is a wasteful number, since it uses less digits than its factorization.

278661220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1804 (or 1802 counting only the distinct ones).

The product of its (nonzero) digits is 16128, while the sum is 34.

The square root of 278661220 is about 16693.1488940823. The cubic root of 278661220 is about 653.1689200565.

The spelling of 278661220 in words is "two hundred seventy-eight million, six hundred sixty-one thousand, two hundred twenty".