12191921 has 8 divisors (see below), whose sum is σ = 13964544. Its totient is φ = 10427040.

The previous prime is 12191917. The next prime is 12191947. The reversal of 12191921 is 12919121.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 12191921 - 2² = 12191917 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12191021) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1976 + ... + 5318.

It is an arithmetic number, because the mean of its divisors is an integer number (1745568).

Almost surely, 2^12191921 is an apocalyptic number.

It is an amenable number.

12191921 is a deficient number, since it is larger than the sum of its proper divisors (1772623).

12191921 is an equidigital number, since it uses as much as digits as its factorization.

12191921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3871.

The product of its digits is 324, while the sum is 26.

The square root of 12191921 is about 3491.6931423022. The cubic root of 12191921 is about 230.1569250445.

The spelling of 12191921 in words is "twelve million, one hundred ninety-one thousand, nine hundred twenty-one".