1287791 has 4 divisors (see below), whose sum is σ = 1293552. Its totient is φ = 1282032.

The previous prime is 1287787. The next prime is 1287799. The reversal of 1287791 is 1977821.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1287791 - 2² = 1287787 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 (1287799) 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 in 3 ways as a sum of consecutive naturals, for example, 2531 + ... + 2996.

It is an arithmetic number, because the mean of its divisors is an integer number (323388).

2^1287791 is an apocalyptic number.

1287791 is a deficient number, since it is larger than the sum of its proper divisors (5761).

1287791 is an equidigital number, since it uses as much as digits as its factorization.

1287791 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5760.

The product of its digits is 7056, while the sum is 35.

The square root of 1287791 is about 1134.8087944672. The cubic root of 1287791 is about 108.7965511720.

The spelling of 1287791 in words is "one million, two hundred eighty-seven thousand, seven hundred ninety-one".