404225021 has 4 divisors (see below), whose sum is σ = 404288412. Its totient is φ = 404161632.

The previous prime is 404225009. The next prime is 404225047. The reversal of 404225021 is 120522404.

It is a happy number.

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 10797796 + 393427225 = 3286^2 + 19835^2 .

It is a cyclic number.

It is not a de Polignac number, because 404225021 - 2¹⁰ = 404223997 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 404224984 and 404225002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (404225821) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20906 + ... + 35291.

It is an arithmetic number, because the mean of its divisors is an integer number (101072103).

Almost surely, 2^404225021 is an apocalyptic number.

It is an amenable number.

404225021 is a deficient number, since it is larger than the sum of its proper divisors (63391).

404225021 is an equidigital number, since it uses as much as digits as its factorization.

404225021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 63390.

The product of its (nonzero) digits is 640, while the sum is 20.

The square root of 404225021 is about 20105.3480696058. The cubic root of 404225021 is about 739.3914042868.

Adding to 404225021 its reverse (120522404), we get a palindrome (524747425).

The spelling of 404225021 in words is "four hundred four million, two hundred twenty-five thousand, twenty-one".