278991945 has 28 divisors (see below), whose sum is σ = 501962436. Its totient is φ = 148793760.

The previous prime is 278991917. The next prime is 278991961. The reversal of 278991945 is 549199872.

It can be written as a sum of positive squares in 2 ways, for example, as 76527504 + 202464441 = 8748^2 + 14229^2 .

It is not a de Polignac number, because 278991945 - 2²² = 274797641 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 278991891 and 278991900.

It is an unprimeable number.

It is a polite number, since it can be written in 27 ways as a sum of consecutive naturals, for example, 34626 + ... + 41915.

Almost surely, 2^278991945 is an apocalyptic number.

It is an amenable number.

278991945 is a deficient number, since it is larger than the sum of its proper divisors (222970491).

278991945 is an frugal number, since it uses more digits than its factorization.

278991945 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 76564 (or 76549 counting only the distinct ones).

The product of its digits is 1632960, while the sum is 54.

The square root of 278991945 is about 16703.0519666317. The cubic root of 278991945 is about 653.4272192290.

It can be divided in two parts, 278991 and 945, that added together give a 7-th power (279936 = 6⁷).

The spelling of 278991945 in words is "two hundred seventy-eight million, nine hundred ninety-one thousand, nine hundred forty-five".