278039989 has 2 divisors, whose sum is σ = 278039990. Its totient is φ = 278039988.

The previous prime is 278039987. The next prime is 278040041. The reversal of 278039989 is 989930872.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 270339364 + 7700625 = 16442^2 + 2775^2 .

It is a cyclic number.

It is not a de Polignac number, because 278039989 - 2¹ = 278039987 is a prime.

Together with 278039987, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (278039987) 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, 139019994 + 139019995.

It is an arithmetic number, because the mean of its divisors is an integer number (139019995).

Almost surely, 2^278039989 is an apocalyptic number.

It is an amenable number.

278039989 is a deficient number, since it is larger than the sum of its proper divisors (1).

278039989 is an equidigital number, since it uses as much as digits as its factorization.

278039989 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1959552, while the sum is 55.

The square root of 278039989 is about 16674.5311478314. The cubic root of 278039989 is about 652.6831800747.

The spelling of 278039989 in words is "two hundred seventy-eight million, thirty-nine thousand, nine hundred eighty-nine".