1391287 has 2 divisors, whose sum is σ = 1391288. Its totient is φ = 1391286.

The previous prime is 1391281. The next prime is 1391317. The reversal of 1391287 is 7821931.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1391287 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 (1391281) 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, 695643 + 695644.

It is an arithmetic number, because the mean of its divisors is an integer number (695644).

2^1391287 is an apocalyptic number.

1391287 is a deficient number, since it is larger than the sum of its proper divisors (1).

1391287 is an equidigital number, since it uses as much as digits as its factorization.

1391287 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3024, while the sum is 31.

The square root of 1391287 is about 1179.5282955487. The cubic root of 1391287 is about 111.6363364075.

The spelling of 1391287 in words is "one million, three hundred ninety-one thousand, two hundred eighty-seven".