278728461 has 54 divisors (see below), whose sum is σ = 467711790. Its totient is φ = 159809760.

The previous prime is 278728441. The next prime is 278728469. The reversal of 278728461 is 164827872.

It can be written as a sum of positive squares in only one way, i.e., 190274436 + 88454025 = 13794^2 + 9405^2 .

It is not a de Polignac number, because 278728461 - 2⁶ = 278728397 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (278728469) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 53 ways as a sum of consecutive naturals, for example, 392775 + ... + 393483.

Almost surely, 2^278728461 is an apocalyptic number.

It is an amenable number.

278728461 is a deficient number, since it is larger than the sum of its proper divisors (188983329).

278728461 is a wasteful number, since it uses less digits than its factorization.

278728461 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 775 (or 742 counting only the distinct ones).

The product of its digits is 301056, while the sum is 45.

The square root of 278728461 is about 16695.1628024407. The cubic root of 278728461 is about 653.2214524220.

The spelling of 278728461 in words is "two hundred seventy-eight million, seven hundred twenty-eight thousand, four hundred sixty-one".