404002021 has 2 divisors, whose sum is σ = 404002022. Its totient is φ = 404002020.

The previous prime is 404002019. The next prime is 404002031. The reversal of 404002021 is 120200404.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 357625921 + 46376100 = 18911^2 + 6810^2 .

It is a cyclic number.

It is not a de Polignac number, because 404002021 - 2¹ = 404002019 is a prime.

Together with 404002019, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 404001992 and 404002010.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (404002031) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 202001010 + 202001011.

It is an arithmetic number, because the mean of its divisors is an integer number (202001011).

Almost surely, 2^404002021 is an apocalyptic number.

It is an amenable number.

404002021 is a deficient number, since it is larger than the sum of its proper divisors (1).

404002021 is an equidigital number, since it uses as much as digits as its factorization.

404002021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 64, while the sum is 13.

The square root of 404002021 is about 20099.8015164329. The cubic root of 404002021 is about 739.2554118696.

Adding to 404002021 its reverse (120200404), we get a palindrome (524202425).

The spelling of 404002021 in words is "four hundred four million, two thousand, twenty-one".