8356421 has 2 divisors, whose sum is σ = 8356422. Its totient is φ = 8356420.

The previous prime is 8356417. The next prime is 8356423. The reversal of 8356421 is 1246538.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 5428900 + 2927521 = 2330^2 + 1711^2 .

It is a cyclic number.

It is not a de Polignac number, because 8356421 - 2² = 8356417 is a prime.

Together with 8356423, 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 (8356423) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4178210 + 4178211.

It is an arithmetic number, because the mean of its divisors is an integer number (4178211).

Almost surely, 2^8356421 is an apocalyptic number.

It is an amenable number.

8356421 is a deficient number, since it is larger than the sum of its proper divisors (1).

8356421 is an equidigital number, since it uses as much as digits as its factorization.

8356421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5760, while the sum is 29.

The square root of 8356421 is about 2890.7474811889. The cubic root of 8356421 is about 202.9271256780.

The spelling of 8356421 in words is "eight million, three hundred fifty-six thousand, four hundred twenty-one".