278889139 has 2 divisors, whose sum is σ = 278889140. Its totient is φ = 278889138.

The previous prime is 278889137. The next prime is 278889161. The reversal of 278889139 is 931988872.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 278889139 - 2¹ = 278889137 is a prime.

It is a super-2 number, since 2×278889139² = 155558303704322642, which contains 22 as substring.

Together with 278889137, 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 278889139.

It is not a weakly prime, because it can be changed into another prime (278889137) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 139444569 + 139444570.

It is an arithmetic number, because the mean of its divisors is an integer number (139444570).

Almost surely, 2^278889139 is an apocalyptic number.

278889139 is a deficient number, since it is larger than the sum of its proper divisors (1).

278889139 is an equidigital number, since it uses as much as digits as its factorization.

278889139 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1741824, while the sum is 55.

The square root of 278889139 is about 16699.9742215370. The cubic root of 278889139 is about 653.3469487016.

The spelling of 278889139 in words is "two hundred seventy-eight million, eight hundred eighty-nine thousand, one hundred thirty-nine".