12103991 has 4 divisors (see below), whose sum is σ = 12521400. Its totient is φ = 11686584.

The previous prime is 12103967. The next prime is 12103997. The reversal of 12103991 is 19930121.

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

It is a cyclic number.

It is not a de Polignac number, because 12103991 - 2¹⁸ = 11841847 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 12103991.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12103997) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 208661 + ... + 208718.

It is an arithmetic number, because the mean of its divisors is an integer number (3130350).

Almost surely, 2^12103991 is an apocalyptic number.

12103991 is a deficient number, since it is larger than the sum of its proper divisors (417409).

12103991 is an equidigital number, since it uses as much as digits as its factorization.

12103991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 417408.

The product of its (nonzero) digits is 486, while the sum is 26.

The square root of 12103991 is about 3479.0790448048. The cubic root of 12103991 is about 229.6022805178.

The spelling of 12103991 in words is "twelve million, one hundred three thousand, nine hundred ninety-one".