1278191 has 2 divisors, whose sum is σ = 1278192. Its totient is φ = 1278190.

The previous prime is 1278181. The next prime is 1278197. The reversal of 1278191 is 1918721.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1278191 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1278197) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 639095 + 639096.

It is an arithmetic number, because the mean of its divisors is an integer number (639096).

2^1278191 is an apocalyptic number.

1278191 is a deficient number, since it is larger than the sum of its proper divisors (1).

1278191 is an equidigital number, since it uses as much as digits as its factorization.

1278191 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1008, while the sum is 29.

The square root of 1278191 is about 1130.5710946243. The cubic root of 1278191 is about 108.5255307415.

The spelling of 1278191 in words is "one million, two hundred seventy-eight thousand, one hundred ninety-one".