8421709 has 2 divisors, whose sum is σ = 8421710. Its totient is φ = 8421708.

The previous prime is 8421701. The next prime is 8421713. The reversal of 8421709 is 9071248.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 8122500 + 299209 = 2850^2 + 547^2 .

It is a cyclic number.

It is not a de Polignac number, because 8421709 - 2³ = 8421701 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8421701) 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, 4210854 + 4210855.

It is an arithmetic number, because the mean of its divisors is an integer number (4210855).

Almost surely, 2^8421709 is an apocalyptic number.

It is an amenable number.

8421709 is a deficient number, since it is larger than the sum of its proper divisors (1).

8421709 is an equidigital number, since it uses as much as digits as its factorization.

8421709 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4032, while the sum is 31.

The square root of 8421709 is about 2902.0180909154. The cubic root of 8421709 is about 203.4542393590.

The spelling of 8421709 in words is "eight million, four hundred twenty-one thousand, seven hundred nine".