278666487 has 20 divisors (see below), whose sum is σ = 454124616. Its totient is φ = 168888240.

The previous prime is 278666473. The next prime is 278666491. The reversal of 278666487 is 784666872.

It is not a de Polignac number, because 278666487 - 2⁸ = 278666231 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (278666447) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 155488 + ... + 157269.

Almost surely, 2^278666487 is an apocalyptic number.

278666487 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

278666487 is a deficient number, since it is larger than the sum of its proper divisors (175458129).

278666487 is a wasteful number, since it uses less digits than its factorization.

278666487 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 312780 (or 312771 counting only the distinct ones).

The product of its digits is 5419008, while the sum is 54.

The square root of 278666487 is about 16693.3066526677. The cubic root of 278666487 is about 653.1730352315.

The spelling of 278666487 in words is "two hundred seventy-eight million, six hundred sixty-six thousand, four hundred eighty-seven".