8211421 has 2 divisors, whose sum is σ = 8211422. Its totient is φ = 8211420.

The previous prime is 8211403. The next prime is 8211433. The reversal of 8211421 is 1241128.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 7868025 + 343396 = 2805^2 + 586^2 .

It is a cyclic number.

It is not a de Polignac number, because 8211421 - 2⁵ = 8211389 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8211461) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4105710 + 4105711.

It is an arithmetic number, because the mean of its divisors is an integer number (4105711).

Almost surely, 2^8211421 is an apocalyptic number.

It is an amenable number.

8211421 is a deficient number, since it is larger than the sum of its proper divisors (1).

8211421 is an equidigital number, since it uses as much as digits as its factorization.

8211421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 128, while the sum is 19.

The square root of 8211421 is about 2865.5577118599. The cubic root of 8211421 is about 201.7465451691.

Adding to 8211421 its reverse (1241128), we get a palindrome (9452549).

The spelling of 8211421 in words is "eight million, two hundred eleven thousand, four hundred twenty-one".