420405561 has 12 divisors (see below), whose sum is σ = 607496292. Its totient is φ = 280157856.

The previous prime is 420405551. The next prime is 420405577. The reversal of 420405561 is 165504024.

It can be written as a sum of positive squares in 2 ways, for example, as 188787600 + 231617961 = 13740^2 + 15219^2 .

It is not a de Polignac number, because 420405561 - 2⁶ = 420405497 is a prime.

It is not an unprimeable number, because it can be changed into a prime (420405511) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 18715 + ... + 34511.

It is an arithmetic number, because the mean of its divisors is an integer number (50624691).

Almost surely, 2^420405561 is an apocalyptic number.

It is an amenable number.

420405561 is a deficient number, since it is larger than the sum of its proper divisors (187090731).

420405561 is a wasteful number, since it uses less digits than its factorization.

420405561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18760 (or 18757 counting only the distinct ones).

The product of its (nonzero) digits is 4800, while the sum is 27.

The square root of 420405561 is about 20503.7938196813. The cubic root of 420405561 is about 749.1282083651.

Adding to 420405561 its reverse (165504024), we get a palindrome (585909585).

The spelling of 420405561 in words is "four hundred twenty million, four hundred five thousand, five hundred sixty-one".