278687 has 2 divisors, whose sum is σ = 278688. Its totient is φ = 278686.

The previous prime is 278671. The next prime is 278689. The reversal of 278687 is 786872.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 278687 - 2⁴ = 278671 is a prime.

Together with 278689, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 278687.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 278687.

It is not a weakly prime, because it can be changed into another prime (278689) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 139343 + 139344.

It is an arithmetic number, because the mean of its divisors is an integer number (139344).

2²⁷⁸⁶⁸⁷ is an apocalyptic number.

278687 is a deficient number, since it is larger than the sum of its proper divisors (1).

278687 is an equidigital number, since it uses as much as digits as its factorization.

278687 is an evil number, because the sum of its binary digits is even.

The product of its digits is 37632, while the sum is 38.

The square root of 278687 is about 527.9081359479. The cubic root of 278687 is about 65.3189061808.

The spelling of 278687 in words is "two hundred seventy-eight thousand, six hundred eighty-seven".