11991331 has 8 divisors (see below), whose sum is σ = 13248000. Its totient is φ = 10762440.

The previous prime is 11991313. The next prime is 11991373. The reversal of 11991331 is 13319911.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 11991331 - 2¹¹ = 11989283 is a prime.

It is a super-2 number, since 2×11991331² = 287584038303122, which contains 22 as substring.

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 11991331.

It is not an unprimeable number, because it can be changed into a prime (11991131) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6031 + ... + 7768.

It is an arithmetic number, because the mean of its divisors is an integer number (1656000).

Almost surely, 2^11991331 is an apocalyptic number.

11991331 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

11991331 is a deficient number, since it is larger than the sum of its proper divisors (1256669).

11991331 is a wasteful number, since it uses less digits than its factorization.

11991331 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13889.

The product of its digits is 729, while the sum is 28.

The square root of 11991331 is about 3462.8501267020. The cubic root of 11991331 is about 228.8877045197.

The spelling of 11991331 in words is "eleven million, nine hundred ninety-one thousand, three hundred thirty-one".