12191999 has 4 divisors (see below), whose sum is σ = 12226320. Its totient is φ = 12157680.

The previous prime is 12191947. The next prime is 12192017. The reversal of 12191999 is 99919121.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-12191999 is a prime.

It is a super-3 number, since 3×12191999³ (a number of 22 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12191299) 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, 16622 + ... + 17339.

It is an arithmetic number, because the mean of its divisors is an integer number (3056580).

Almost surely, 2^12191999 is an apocalyptic number.

12191999 is a deficient number, since it is larger than the sum of its proper divisors (34321).

12191999 is an equidigital number, since it uses as much as digits as its factorization.

12191999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34320.

The product of its digits is 13122, while the sum is 41.

The square root of 12191999 is about 3491.7043116507. The cubic root of 12191999 is about 230.1574158668.

The spelling of 12191999 in words is "twelve million, one hundred ninety-one thousand, nine hundred ninety-nine".