404500021 has 4 divisors (see below), whose sum is σ = 415432492. Its totient is φ = 393567552.

The previous prime is 404500013. The next prime is 404500043. The reversal of 404500021 is 120005404.

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 197543025 + 206956996 = 14055^2 + 14386^2 .

It is a cyclic number.

It is not a de Polignac number, because 404500021 - 2³ = 404500013 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 404499968 and 404500004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (404500321) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5466180 + ... + 5466253.

It is an arithmetic number, because the mean of its divisors is an integer number (103858123).

Almost surely, 2^404500021 is an apocalyptic number.

It is an amenable number.

404500021 is a deficient number, since it is larger than the sum of its proper divisors (10932471).

404500021 is a wasteful number, since it uses less digits than its factorization.

404500021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10932470.

The product of its (nonzero) digits is 160, while the sum is 16.

The square root of 404500021 is about 20112.1858831903. The cubic root of 404500021 is about 739.5590390884.

Adding to 404500021 its reverse (120005404), we get a palindrome (524505425).

The spelling of 404500021 in words is "four hundred four million, five hundred thousand, twenty-one".