420565 has 12 divisors (see below), whose sum is σ = 534924. Its totient is φ = 317376.

The previous prime is 420557. The next prime is 420569. The reversal of 420565 is 565024.

It can be written as a sum of positive squares in 2 ways, for example, as 116964 + 303601 = 342^2 + 551^2 .

It is not a de Polignac number, because 420565 - 2³ = 420557 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (420569) 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 in 11 ways as a sum of consecutive naturals, for example, 1689 + ... + 1921.

It is an arithmetic number, because the mean of its divisors is an integer number (44577).

2⁴²⁰⁵⁶⁵ is an apocalyptic number.

It is an amenable number.

420565 is a deficient number, since it is larger than the sum of its proper divisors (114359).

420565 is a wasteful number, since it uses less digits than its factorization.

420565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 276 (or 257 counting only the distinct ones).

The product of its (nonzero) digits is 1200, while the sum is 22.

The square root of 420565 is about 648.5098303033. The cubic root of 420565 is about 74.9222898800.

Adding to 420565 its reverse (565024), we get a palindrome (985589).

The spelling of 420565 in words is "four hundred twenty thousand, five hundred sixty-five".