278456779 has 4 divisors (see below), whose sum is σ = 279077400. Its totient is φ = 277836160.

The previous prime is 278456767. The next prime is 278456803. The reversal of 278456779 is 977654872.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 278456779 - 2¹¹ = 278454731 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (278456179) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 309637 + ... + 310534.

It is an arithmetic number, because the mean of its divisors is an integer number (69769350).

Almost surely, 2^278456779 is an apocalyptic number.

278456779 is a deficient number, since it is larger than the sum of its proper divisors (620621).

278456779 is an equidigital number, since it uses as much as digits as its factorization.

278456779 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 620620.

The product of its digits is 5927040, while the sum is 55.

The square root of 278456779 is about 16687.0242703725. The cubic root of 278456779 is about 653.0091475837.

The spelling of 278456779 in words is "two hundred seventy-eight million, four hundred fifty-six thousand, seven hundred seventy-nine".