1291287 has 8 divisors (see below), whose sum is σ = 1727104. Its totient is φ = 858168.

The previous prime is 1291271. The next prime is 1291313. The reversal of 1291287 is 7821921.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1291287 - 2⁴ = 1291271 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 (1291217) 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 7 ways as a sum of consecutive naturals, for example, 1158 + ... + 1980.

It is an arithmetic number, because the mean of its divisors is an integer number (215888).

2^1291287 is an apocalyptic number.

1291287 is a deficient number, since it is larger than the sum of its proper divisors (435817).

1291287 is an equidigital number, since it uses as much as digits as its factorization.

1291287 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1349.

The product of its digits is 2016, while the sum is 30.

The square root of 1291287 is about 1136.3480980756. The cubic root of 1291287 is about 108.8949131672.

The spelling of 1291287 in words is "one million, two hundred ninety-one thousand, two hundred eighty-seven".