12345991 has 24 divisors (see below), whose sum is σ = 15390000. Its totient is φ = 9846144.

The previous prime is 12345959. The next prime is 12346013. The reversal of 12345991 is 19954321.

12345991 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 12345991 - 2⁵ = 12345959 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12345191) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 82785 + ... + 82933.

It is an arithmetic number, because the mean of its divisors is an integer number (641250).

Almost surely, 2^12345991 is an apocalyptic number.

12345991 is a deficient number, since it is larger than the sum of its proper divisors (3044009).

12345991 is a wasteful number, since it uses less digits than its factorization.

12345991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 271 (or 264 counting only the distinct ones).

The product of its digits is 9720, while the sum is 34.

The square root of 12345991 is about 3513.6862409726. The cubic root of 12345991 is about 231.1223716486.

It can be divided in two parts, 1234 and 5991, that added together give a square (7225 = 85²).

The spelling of 12345991 in words is "twelve million, three hundred forty-five thousand, nine hundred ninety-one".