12166421 has 2 divisors, whose sum is σ = 12166422. Its totient is φ = 12166420.

The previous prime is 12166393. The next prime is 12166423. The reversal of 12166421 is 12466121.

12166421 is digitally balanced in base 2 and base 3, because in such bases it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 8008900 + 4157521 = 2830^2 + 2039^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-12166421 is a prime.

Together with 12166423, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12166423) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6083210 + 6083211.

It is an arithmetic number, because the mean of its divisors is an integer number (6083211).

Almost surely, 2^12166421 is an apocalyptic number.

It is an amenable number.

12166421 is a deficient number, since it is larger than the sum of its proper divisors (1).

12166421 is an equidigital number, since it uses as much as digits as its factorization.

12166421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 576, while the sum is 23.

The square root of 12166421 is about 3488.0397073428. The cubic root of 12166421 is about 229.9963515489.

The spelling of 12166421 in words is "twelve million, one hundred sixty-six thousand, four hundred twenty-one".