12191918 has 4 divisors (see below), whose sum is σ = 18287880. Its totient is φ = 6095958.

The previous prime is 12191917. The next prime is 12191947. The reversal of 12191918 is 81919121.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12191917) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3047978 + ... + 3047981.

It is an arithmetic number, because the mean of its divisors is an integer number (4571970).

Almost surely, 2^12191918 is an apocalyptic number.

12191918 is a deficient number, since it is larger than the sum of its proper divisors (6095962).

12191918 is an equidigital number, since it uses as much as digits as its factorization.

12191918 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6095961.

The product of its digits is 1296, while the sum is 32.

The square root of 12191918 is about 3491.6927127111. The cubic root of 12191918 is about 230.1569061667.

The spelling of 12191918 in words is "twelve million, one hundred ninety-one thousand, nine hundred eighteen".