8420509 has 2 divisors, whose sum is σ = 8420510. Its totient is φ = 8420508.

The previous prime is 8420483. The next prime is 8420519. The reversal of 8420509 is 9050248.

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., 8139609 + 280900 = 2853^2 + 530^2 .

It is a cyclic number.

It is not a de Polignac number, because 8420509 - 2¹³ = 8412317 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8420519) 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, 4210254 + 4210255.

It is an arithmetic number, because the mean of its divisors is an integer number (4210255).

Almost surely, 2^8420509 is an apocalyptic number.

It is an amenable number.

8420509 is a deficient number, since it is larger than the sum of its proper divisors (1).

8420509 is an equidigital number, since it uses as much as digits as its factorization.

8420509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2880, while the sum is 28.

The square root of 8420509 is about 2901.8113308759. The cubic root of 8420509 is about 203.4445755768. Note that the first 3 decimals are identical.

The spelling of 8420509 in words is "eight million, four hundred twenty thousand, five hundred nine".