420400205 has 4 divisors (see below), whose sum is σ = 504480252. Its totient is φ = 336320160.

The previous prime is 420400199. The next prime is 420400223. The reversal of 420400205 is 502004024.

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

It can be written as a sum of positive squares in 2 ways, for example, as 125865961 + 294534244 = 11219^2 + 17162^2 .

It is not a de Polignac number, because 420400205 - 2¹⁰ = 420399181 is a prime.

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, 42040016 + ... + 42040025.

It is an arithmetic number, because the mean of its divisors is an integer number (126120063).

Almost surely, 2^420400205 is an apocalyptic number.

It is an amenable number.

420400205 is a deficient number, since it is larger than the sum of its proper divisors (84080047).

420400205 is an equidigital number, since it uses as much as digits as its factorization.

420400205 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 84080046.

The product of its (nonzero) digits is 320, while the sum is 17.

The square root of 420400205 is about 20503.6632092902. The cubic root of 420400205 is about 749.1250270341.

Adding to 420400205 its reverse (502004024), we get a palindrome (922404229).

The spelling of 420400205 in words is "four hundred twenty million, four hundred thousand, two hundred five".