8557421 has 2 divisors, whose sum is σ = 8557422. Its totient is φ = 8557420.

The previous prime is 8557411. The next prime is 8557447. The reversal of 8557421 is 1247558.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 8185321 + 372100 = 2861^2 + 610^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-8557421 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8557411) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4278710 + 4278711.

It is an arithmetic number, because the mean of its divisors is an integer number (4278711).

Almost surely, 2^8557421 is an apocalyptic number.

It is an amenable number.

8557421 is a deficient number, since it is larger than the sum of its proper divisors (1).

8557421 is an equidigital number, since it uses as much as digits as its factorization.

8557421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 11200, while the sum is 32.

The square root of 8557421 is about 2925.3069924369. The cubic root of 8557421 is about 204.5412784841.

The spelling of 8557421 in words is "eight million, five hundred fifty-seven thousand, four hundred twenty-one".