420520405 has 4 divisors (see below), whose sum is σ = 504624492. Its totient is φ = 336416320.

The previous prime is 420520393. The next prime is 420520417. The reversal of 420520405 is 504025024.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (420520393) and next prime (420520417).

It can be written as a sum of positive squares in 2 ways, for example, as 232227121 + 188293284 = 15239^2 + 13722^2 .

It is not a de Polignac number, because 420520405 - 2⁹ = 420519893 is a prime.

It is a super-2 number, since 2×420520405² = 353674822042728050, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 42052036 + ... + 42052045.

It is an arithmetic number, because the mean of its divisors is an integer number (126156123).

Almost surely, 2^420520405 is an apocalyptic number.

It is an amenable number.

420520405 is a deficient number, since it is larger than the sum of its proper divisors (84104087).

420520405 is an equidigital number, since it uses as much as digits as its factorization.

420520405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 84104086.

The product of its (nonzero) digits is 1600, while the sum is 22.

The square root of 420520405 is about 20506.5941833353. The cubic root of 420520405 is about 749.1964163490.

Adding to 420520405 its reverse (504025024), we get a palindrome (924545429).

The spelling of 420520405 in words is "four hundred twenty million, five hundred twenty thousand, four hundred five".