1288691 has 2 divisors, whose sum is σ = 1288692. Its totient is φ = 1288690.

The previous prime is 1288657. The next prime is 1288697. The reversal of 1288691 is 1968821.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1288691 - 2¹⁸ = 1026547 is a prime.

It is not a weakly prime, because it can be changed into another prime (1288697) 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, 644345 + 644346.

It is an arithmetic number, because the mean of its divisors is an integer number (644346).

2^1288691 is an apocalyptic number.

1288691 is a deficient number, since it is larger than the sum of its proper divisors (1).

1288691 is an equidigital number, since it uses as much as digits as its factorization.

1288691 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6912, while the sum is 35.

The square root of 1288691 is about 1135.2052677820. The cubic root of 1288691 is about 108.8218901943.

The spelling of 1288691 in words is "one million, two hundred eighty-eight thousand, six hundred ninety-one".