8668421 has 2 divisors, whose sum is σ = 8668422. Its totient is φ = 8668420.

The previous prime is 8668403. The next prime is 8668423. The reversal of 8668421 is 1248668.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 8584900 + 83521 = 2930^2 + 289^2 .

It is a cyclic number.

It is not a de Polignac number, because 8668421 - 2⁶ = 8668357 is a prime.

Together with 8668423, 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 (8668423) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4334210 + 4334211.

It is an arithmetic number, because the mean of its divisors is an integer number (4334211).

Almost surely, 2^8668421 is an apocalyptic number.

It is an amenable number.

8668421 is a deficient number, since it is larger than the sum of its proper divisors (1).

8668421 is an equidigital number, since it uses as much as digits as its factorization.

8668421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 18432, while the sum is 35.

The square root of 8668421 is about 2944.2182324006. The cubic root of 8668421 is about 205.4218637634.

The spelling of 8668421 in words is "eight million, six hundred sixty-eight thousand, four hundred twenty-one".