420402509 has 2 divisors, whose sum is σ = 420402510. Its totient is φ = 420402508.

The previous prime is 420402497. The next prime is 420402517. The reversal of 420402509 is 905204024.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 225660484 + 194742025 = 15022^2 + 13955^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-420402509 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (420402539) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 210201254 + 210201255.

It is an arithmetic number, because the mean of its divisors is an integer number (210201255).

Almost surely, 2^420402509 is an apocalyptic number.

It is an amenable number.

420402509 is a deficient number, since it is larger than the sum of its proper divisors (1).

420402509 is an equidigital number, since it uses as much as digits as its factorization.

420402509 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 26.

The square root of 420402509 is about 20503.7193942953. The cubic root of 420402509 is about 749.1263955562.

The spelling of 420402509 in words is "four hundred twenty million, four hundred two thousand, five hundred nine".