11999111 has 2 divisors, whose sum is σ = 11999112. Its totient is φ = 11999110.

The previous prime is 11999027. The next prime is 11999129. The reversal of 11999111 is 11199911.

It is a strong prime. It is also a bemirp because it and its reverse can be mirrored producing other two distinct primes, 11166611 and 11666111.

It is a cyclic number.

It is not a de Polignac number, because 11999111 - 2²² = 7804807 is a prime.

It is a Chen prime.

It is equal to p₇₈₈₀₀₉ and since 11999111 and 788009 have the same sum of digits, it is a Honaker prime.

It is a zygodrome in base 10.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (11999171) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5999555 + 5999556.

It is an arithmetic number, because the mean of its divisors is an integer number (5999556).

Almost surely, 2^11999111 is an apocalyptic number.

11999111 is a deficient number, since it is larger than the sum of its proper divisors (1).

11999111 is an equidigital number, since it uses as much as digits as its factorization.

11999111 is an evil number, because the sum of its binary digits is even.

The product of its digits is 729, while the sum is 32.

The square root of 11999111 is about 3463.9732966638. The cubic root of 11999111 is about 228.9371947546.

The spelling of 11999111 in words is "eleven million, nine hundred ninety-nine thousand, one hundred eleven".