12191917 has 2 divisors, whose sum is σ = 12191918. Its totient is φ = 12191916.

The previous prime is 12191903. The next prime is 12191947. The reversal of 12191917 is 71919121.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 7650756 + 4541161 = 2766^2 + 2131^2 .

It is a cyclic number.

It is not a de Polignac number, because 12191917 - 2¹¹ = 12189869 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12191947) 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 as a sum of consecutive naturals, namely, 6095958 + 6095959.

It is an arithmetic number, because the mean of its divisors is an integer number (6095959).

Almost surely, 2^12191917 is an apocalyptic number.

It is an amenable number.

12191917 is a deficient number, since it is larger than the sum of its proper divisors (1).

12191917 is an equidigital number, since it uses as much as digits as its factorization.

12191917 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1134, while the sum is 31.

The square root of 12191917 is about 3491.6925695141. The cubic root of 12191917 is about 230.1568998741.

It can be divided in two parts, 1219 and 1917, that added together give a square (3136 = 56²).

The spelling of 12191917 in words is "twelve million, one hundred ninety-one thousand, nine hundred seventeen".