404004431021 has 4 divisors (see below), whose sum is σ = 404015792544. Its totient is φ = 403993069500.

The previous prime is 404004431009. The next prime is 404004431029. The reversal of 404004431021 is 120134400404.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 404004431021 - 2²⁶ = 403937322157 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (404004431029) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5627255 + ... + 5698596.

It is an arithmetic number, because the mean of its divisors is an integer number (101003948136).

Almost surely, 2^404004431021 is an apocalyptic number.

It is an amenable number.

404004431021 is a deficient number, since it is larger than the sum of its proper divisors (11361523).

404004431021 is a wasteful number, since it uses less digits than its factorization.

404004431021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11361522.

The product of its (nonzero) digits is 1536, while the sum is 23.

Adding to 404004431021 its reverse (120134400404), we get a palindrome (524138831425).

The spelling of 404004431021 in words is "four hundred four billion, four million, four hundred thirty-one thousand, twenty-one".