278216820 has 72 divisors (see below), whose sum is σ = 964489344. Its totient is φ = 63592128.

The previous prime is 278216819. The next prime is 278216831. The reversal of 278216820 is 28612872.

It is a happy number.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 109144 + ... + 111663.

Almost surely, 2^278216820 is an apocalyptic number.

278216820 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

278216820 is an abundant number, since it is smaller than the sum of its proper divisors (686272524).

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

278216820 is a wasteful number, since it uses less digits than its factorization.

278216820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 220829 (or 220824 counting only the distinct ones).

The product of its (nonzero) digits is 21504, while the sum is 36.

The square root of 278216820 is about 16679.8327329743. The cubic root of 278216820 is about 652.8215176821.

The spelling of 278216820 in words is "two hundred seventy-eight million, two hundred sixteen thousand, eight hundred twenty".