12218491 has 2 divisors, whose sum is σ = 12218492. Its totient is φ = 12218490.

The previous prime is 12218489. The next prime is 12218509. The reversal of 12218491 is 19481221.

It is a weak prime.

It is an emirp because it is prime and its reverse (19481221) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 12218491 - 2¹ = 12218489 is a prime.

Together with 12218489, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (12218891) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6109245 + 6109246.

It is an arithmetic number, because the mean of its divisors is an integer number (6109246).

Almost surely, 2^12218491 is an apocalyptic number.

12218491 is a deficient number, since it is larger than the sum of its proper divisors (1).

12218491 is an equidigital number, since it uses as much as digits as its factorization.

12218491 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1152, while the sum is 28.

The square root of 12218491 is about 3495.4958160467. The cubic root of 12218491 is about 230.3239983195.

The spelling of 12218491 in words is "twelve million, two hundred eighteen thousand, four hundred ninety-one".