11916991 has 4 divisors (see below), whose sum is σ = 12170592. Its totient is φ = 11663392.

The previous prime is 11916973. The next prime is 11917001. The reversal of 11916991 is 19961911.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19961911 = 131 ⋅152381.

It is a cyclic number.

It is not a de Polignac number, because 11916991 - 2⁵ = 11916959 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 11916991.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11916901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 126730 + ... + 126823.

It is an arithmetic number, because the mean of its divisors is an integer number (3042648).

Almost surely, 2^11916991 is an apocalyptic number.

11916991 is a deficient number, since it is larger than the sum of its proper divisors (253601).

11916991 is an equidigital number, since it uses as much as digits as its factorization.

11916991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 253600.

The product of its digits is 4374, while the sum is 37.

The square root of 11916991 is about 3452.0995060977. The cubic root of 11916991 is about 228.4137288897.

The spelling of 11916991 in words is "eleven million, nine hundred sixteen thousand, nine hundred ninety-one".