12391668 has 18 divisors (see below), whose sum is σ = 31323474. Its totient is φ = 4130544.

The previous prime is 12391663. The next prime is 12391679. The reversal of 12391668 is 86619321.

It can be written as a sum of positive squares in only one way, i.e., 9108324 + 3283344 = 3018^2 + 1812^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a Harshad number since it is a multiple of its sum of digits (36), and also a Moran number because the ratio is a prime number: 344213 = 12391668 / (1 + 2 + 3 + 9 + 1 + 6 + 6 + 8).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12391663) 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 5 ways as a sum of consecutive naturals, for example, 172071 + ... + 172142.

It is an arithmetic number, because the mean of its divisors is an integer number (1740193).

Almost surely, 2^12391668 is an apocalyptic number.

12391668 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

12391668 is an abundant number, since it is smaller than the sum of its proper divisors (18931806).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

12391668 is a wasteful number, since it uses less digits than its factorization.

12391668 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 344223 (or 344218 counting only the distinct ones).

The product of its digits is 15552, while the sum is 36.

The square root of 12391668 is about 3520.1801090285. The cubic root of 12391668 is about 231.4070520196.

The spelling of 12391668 in words is "twelve million, three hundred ninety-one thousand, six hundred sixty-eight".