11991011 has 2 divisors, whose sum is σ = 11991012. Its totient is φ = 11991010.

The previous prime is 11990999. The next prime is 11991013. The reversal of 11991011 is 11019911.

It is a happy number.

It is a strong prime. It is also a bemirp because it and its reverse can be mirrored producing other two distinct primes, 11016611 and 11661011.

It is a cyclic number.

It is not a de Polignac number, because 11991011 - 2⁶ = 11990947 is a prime.

Together with 11991013, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (11991013) 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 as a sum of consecutive naturals, namely, 5995505 + 5995506.

It is an arithmetic number, because the mean of its divisors is an integer number (5995506).

Almost surely, 2^11991011 is an apocalyptic number.

11991011 is a deficient number, since it is larger than the sum of its proper divisors (1).

11991011 is an equidigital number, since it uses as much as digits as its factorization.

11991011 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 81, while the sum is 23.

The square root of 11991011 is about 3462.8039216797. The cubic root of 11991011 is about 228.8856684734.

The spelling of 11991011 in words is "eleven million, nine hundred ninety-one thousand, eleven".