420531809 has 2 divisors, whose sum is σ = 420531810. Its totient is φ = 420531808.

The previous prime is 420531803. The next prime is 420531821. The reversal of 420531809 is 908135024.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 395811025 + 24720784 = 19895^2 + 4972^2 .

It is a cyclic number.

It is not a de Polignac number, because 420531809 - 2¹² = 420527713 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (420531803) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 210265904 + 210265905.

It is an arithmetic number, because the mean of its divisors is an integer number (210265905).

Almost surely, 2^420531809 is an apocalyptic number.

It is an amenable number.

420531809 is a deficient number, since it is larger than the sum of its proper divisors (1).

420531809 is an equidigital number, since it uses as much as digits as its factorization.

420531809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8640, while the sum is 32.

The square root of 420531809 is about 20506.8722383498. The cubic root of 420531809 is about 749.2031887185.

The spelling of 420531809 in words is "four hundred twenty million, five hundred thirty-one thousand, eight hundred nine".