11997591 has 8 divisors (see below), whose sum is σ = 16268160. Its totient is φ = 7862712.

The previous prime is 11997577. The next prime is 11997593. The reversal of 11997591 is 19579911.

It is a happy number.

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

It is not a de Polignac number, because 11997591 - 2⁷ = 11997463 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11997593) 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 7 ways as a sum of consecutive naturals, for example, 33715 + ... + 34068.

It is an arithmetic number, because the mean of its divisors is an integer number (2033520).

Almost surely, 2^11997591 is an apocalyptic number.

11997591 is a deficient number, since it is larger than the sum of its proper divisors (4270569).

11997591 is an equidigital number, since it uses as much as digits as its factorization.

11997591 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 67845.

The product of its digits is 25515, while the sum is 42.

The square root of 11997591 is about 3463.7538884857. The cubic root of 11997591 is about 228.9275273931.

The spelling of 11997591 in words is "eleven million, nine hundred ninety-seven thousand, five hundred ninety-one".