278764991 has 8 divisors (see below), whose sum is σ = 291103584. Its totient is φ = 266444640.

The previous prime is 278764951. The next prime is 278765041. The reversal of 278764991 is 199467872.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 278764991 - 2¹⁴ = 278748607 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (278764901) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 33545 + ... + 41021.

It is an arithmetic number, because the mean of its divisors is an integer number (36387948).

Almost surely, 2^278764991 is an apocalyptic number.

278764991 is a deficient number, since it is larger than the sum of its proper divisors (12338593).

278764991 is a wasteful number, since it uses less digits than its factorization.

278764991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9121.

The product of its digits is 1524096, while the sum is 53.

The square root of 278764991 is about 16696.2567960606. The cubic root of 278764991 is about 653.2499881245.

The spelling of 278764991 in words is "two hundred seventy-eight million, seven hundred sixty-four thousand, nine hundred ninety-one".