12193991 has 4 divisors (see below), whose sum is σ = 12835800. Its totient is φ = 11552184.

The previous prime is 12193969. The next prime is 12193997. The reversal of 12193991 is 19939121.

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-12193991 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12193997) 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 in 3 ways as a sum of consecutive naturals, for example, 320876 + ... + 320913.

It is an arithmetic number, because the mean of its divisors is an integer number (3208950).

Almost surely, 2^12193991 is an apocalyptic number.

12193991 is a deficient number, since it is larger than the sum of its proper divisors (641809).

12193991 is an equidigital number, since it uses as much as digits as its factorization.

12193991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 641808.

The product of its digits is 4374, while the sum is 35.

The square root of 12193991 is about 3491.9895475216. The cubic root of 12193991 is about 230.1699500052.

The spelling of 12193991 in words is "twelve million, one hundred ninety-three thousand, nine hundred ninety-one".