11808537591 has 4 divisors (see below), whose sum is σ = 15744716792. Its totient is φ = 7872358392.

The previous prime is 11808537583. The next prime is 11808537593. The reversal of 11808537591 is 19573580811.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19573580811 = 3 ⋅6524526937.

It is not a de Polignac number, because 11808537591 - 2³ = 11808537583 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 11808537591.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11808537593) 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, 1968089596 + ... + 1968089601.

It is an arithmetic number, because the mean of its divisors is an integer number (3936179198).

Almost surely, 2^11808537591 is an apocalyptic number.

11808537591 is a deficient number, since it is larger than the sum of its proper divisors (3936179201).

11808537591 is an equidigital number, since it uses as much as digits as its factorization.

11808537591 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3936179200.

The product of its (nonzero) digits is 302400, while the sum is 48.

The spelling of 11808537591 in words is "eleven billion, eight hundred eight million, five hundred thirty-seven thousand, five hundred ninety-one".