1278289 has 2 divisors, whose sum is σ = 1278290. Its totient is φ = 1278288.

The previous prime is 1278287. The next prime is 1278323. The reversal of 1278289 is 9828721.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1227664 + 50625 = 1108^2 + 225^2 .

It is a cyclic number.

It is not a de Polignac number, because 1278289 - 2¹ = 1278287 is a prime.

Together with 1278287, it forms a pair of twin primes.

It is a plaindrome in base 13.

It is not a weakly prime, because it can be changed into another prime (1278287) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 639144 + 639145.

It is an arithmetic number, because the mean of its divisors is an integer number (639145).

2^1278289 is an apocalyptic number.

It is an amenable number.

1278289 is a deficient number, since it is larger than the sum of its proper divisors (1).

1278289 is an equidigital number, since it uses as much as digits as its factorization.

1278289 is an evil number, because the sum of its binary digits is even.

The product of its digits is 16128, while the sum is 37.

The square root of 1278289 is about 1130.6144347212. The cubic root of 1278289 is about 108.5283042525.

The spelling of 1278289 in words is "one million, two hundred seventy-eight thousand, two hundred eighty-nine".