278764993 has 24 divisors (see below), whose sum is σ = 313625400. Its totient is φ = 247463424.

The previous prime is 278764951. The next prime is 278765041. The reversal of 278764993 is 399467872.

It can be written as a sum of positive squares in 12 ways, for example, as 12194064 + 266570929 = 3492^2 + 16327^2 .

It is not a de Polignac number, because 278764993 - 2⁹ = 278764481 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 (278764093) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 681373 + ... + 681781.

It is an arithmetic number, because the mean of its divisors is an integer number (13067725).

Almost surely, 2^278764993 is an apocalyptic number.

It is an amenable number.

278764993 is a deficient number, since it is larger than the sum of its proper divisors (34860407).

278764993 is a wasteful number, since it uses less digits than its factorization.

278764993 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 581 (or 568 counting only the distinct ones).

The product of its digits is 4572288, while the sum is 55.

The square root of 278764993 is about 16696.2568559543. The cubic root of 278764993 is about 653.2499896867.

The spelling of 278764993 in words is "two hundred seventy-eight million, seven hundred sixty-four thousand, nine hundred ninety-three".