11811691 has 4 divisors (see below), whose sum is σ = 11819592. Its totient is φ = 11803792.

The previous prime is 11811659. The next prime is 11811697. The reversal of 11811691 is 19611811.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 19611811 = 359 ⋅54629.

It is a cyclic number.

It is not a de Polignac number, because 11811691 - 2⁵ = 11811659 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11811697) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 946 + ... + 4951.

It is an arithmetic number, because the mean of its divisors is an integer number (2954898).

Almost surely, 2^11811691 is an apocalyptic number.

11811691 is a deficient number, since it is larger than the sum of its proper divisors (7901).

11811691 is an equidigital number, since it uses as much as digits as its factorization.

11811691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7900.

The product of its digits is 432, while the sum is 28.

The square root of 11811691 is about 3436.8140770196. The cubic root of 11811691 is about 227.7389736175.

The spelling of 11811691 in words is "eleven million, eight hundred eleven thousand, six hundred ninety-one".