1288391 has 16 divisors (see below), whose sum is σ = 1505280. Its totient is φ = 1092960.

The previous prime is 1288367. The next prime is 1288393. The reversal of 1288391 is 1938821.

It is a de Polignac number, because none of the positive numbers 2^k-1288391 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1288393) 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 in 15 ways as a sum of consecutive naturals, for example, 9200 + ... + 9338.

It is an arithmetic number, because the mean of its divisors is an integer number (94080).

2^1288391 is an apocalyptic number.

1288391 is a deficient number, since it is larger than the sum of its proper divisors (216889).

1288391 is a wasteful number, since it uses less digits than its factorization.

1288391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 206.

The product of its digits is 3456, while the sum is 32.

The square root of 1288391 is about 1135.0731253977. The cubic root of 1288391 is about 108.8134451648.

The spelling of 1288391 in words is "one million, two hundred eighty-eight thousand, three hundred ninety-one".