11991801 has 4 divisors (see below), whose sum is σ = 15989072. Its totient is φ = 7994532.

The previous prime is 11991781. The next prime is 11991839. The reversal of 11991801 is 10819911.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 11991801 - 2¹⁰ = 11990777 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11991601) 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, 1998631 + ... + 1998636.

It is an arithmetic number, because the mean of its divisors is an integer number (3997268).

Almost surely, 2^11991801 is an apocalyptic number.

It is an amenable number.

11991801 is a deficient number, since it is larger than the sum of its proper divisors (3997271).

11991801 is an equidigital number, since it uses as much as digits as its factorization.

11991801 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3997270.

The product of its (nonzero) digits is 648, while the sum is 30.

The square root of 11991801 is about 3462.9179892108. The cubic root of 11991801 is about 228.8906948971.

The spelling of 11991801 in words is "eleven million, nine hundred ninety-one thousand, eight hundred one".