278606987 has 2 divisors, whose sum is σ = 278606988. Its totient is φ = 278606986.

The previous prime is 278606983. The next prime is 278607011. The reversal of 278606987 is 789606872.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 278606987 - 2² = 278606983 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (278606983) 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 as a sum of consecutive naturals, namely, 139303493 + 139303494.

It is an arithmetic number, because the mean of its divisors is an integer number (139303494).

Almost surely, 2^278606987 is an apocalyptic number.

278606987 is a deficient number, since it is larger than the sum of its proper divisors (1).

278606987 is an equidigital number, since it uses as much as digits as its factorization.

278606987 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2032128, while the sum is 53.

The square root of 278606987 is about 16691.5244061170. The cubic root of 278606987 is about 653.1265440987.

The spelling of 278606987 in words is "two hundred seventy-eight million, six hundred six thousand, nine hundred eighty-seven".