12297991 has 4 divisors (see below), whose sum is σ = 12597984. Its totient is φ = 11998000.

The previous prime is 12297983. The next prime is 12298007. The reversal of 12297991 is 19979221.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19979221 = 31 ⋅644491.

It is a cyclic number.

It is not a de Polignac number, because 12297991 - 2³ = 12297983 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12297941) 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, 149935 + ... + 150016.

It is an arithmetic number, because the mean of its divisors is an integer number (3149496).

Almost surely, 2^12297991 is an apocalyptic number.

12297991 is a deficient number, since it is larger than the sum of its proper divisors (299993).

12297991 is an equidigital number, since it uses as much as digits as its factorization.

12297991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 299992.

The product of its digits is 20412, while the sum is 40.

The square root of 12297991 is about 3506.8491555811. The cubic root of 12297991 is about 230.8224556064.

The spelling of 12297991 in words is "twelve million, two hundred ninety-seven thousand, nine hundred ninety-one".