420740809 has 2 divisors, whose sum is σ = 420740810. Its totient is φ = 420740808.

The previous prime is 420740797. The next prime is 420740833. The reversal of 420740809 is 908047024.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 395015625 + 25725184 = 19875^2 + 5072^2 .

It is a cyclic number.

It is not a de Polignac number, because 420740809 - 2⁹ = 420740297 is a prime.

It is not a weakly prime, because it can be changed into another prime (420740849) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 210370404 + 210370405.

It is an arithmetic number, because the mean of its divisors is an integer number (210370405).

Almost surely, 2^420740809 is an apocalyptic number.

It is an amenable number.

420740809 is a deficient number, since it is larger than the sum of its proper divisors (1).

420740809 is an equidigital number, since it uses as much as digits as its factorization.

420740809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 16128, while the sum is 34.

The square root of 420740809 is about 20511.9674580475. The cubic root of 420740809 is about 749.3272835987.

The spelling of 420740809 in words is "four hundred twenty million, seven hundred forty thousand, eight hundred nine".