11991211 has 4 divisors (see below), whose sum is σ = 12512592. Its totient is φ = 11469832.

The previous prime is 11991209. The next prime is 11991233. The reversal of 11991211 is 11219911.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 11219911 = 2593 ⋅4327.

It is a cyclic number.

It is not a de Polignac number, because 11991211 - 2¹ = 11991209 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11991241) 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, 260656 + ... + 260701.

It is an arithmetic number, because the mean of its divisors is an integer number (3128148).

Almost surely, 2^11991211 is an apocalyptic number.

11991211 is a deficient number, since it is larger than the sum of its proper divisors (521381).

11991211 is an equidigital number, since it uses as much as digits as its factorization.

11991211 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 521380.

The product of its digits is 162, while the sum is 25.

The square root of 11991211 is about 3462.8327998909. The cubic root of 11991211 is about 228.8869410066.

The spelling of 11991211 in words is "eleven million, nine hundred ninety-one thousand, two hundred eleven".