1327991 has 4 divisors (see below), whose sum is σ = 1517712. Its totient is φ = 1138272.

The previous prime is 1327987. The next prime is 1327999. The reversal of 1327991 is 1997231.

It is a happy number.

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 1327991 - 2² = 1327987 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1327999) 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 3 ways as a sum of consecutive naturals, for example, 94850 + ... + 94863.

It is an arithmetic number, because the mean of its divisors is an integer number (379428).

2^1327991 is an apocalyptic number.

1327991 is a deficient number, since it is larger than the sum of its proper divisors (189721).

1327991 is an equidigital number, since it uses as much as digits as its factorization.

1327991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 189720.

The product of its digits is 3402, while the sum is 32.

The square root of 1327991 is about 1152.3849183324. The cubic root of 1327991 is about 109.9170448942.

The spelling of 1327991 in words is "one million, three hundred twenty-seven thousand, nine hundred ninety-one".