404002120021 has 4 divisors (see below), whose sum is σ = 404006586732. Its totient is φ = 403997653312.

The previous prime is 404002119991. The next prime is 404002120031. The reversal of 404002120021 is 120021200404.

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 120457584900 + 283544535121 = 347070^2 + 532489^2 .

It is a cyclic number.

It is not a de Polignac number, because 404002120021 - 2⁷ = 404002119893 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 404002119977 and 404002120004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (404002120031) 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, 2094820 + ... + 2279533.

It is an arithmetic number, because the mean of its divisors is an integer number (101001646683).

Almost surely, 2^404002120021 is an apocalyptic number.

It is an amenable number.

404002120021 is a deficient number, since it is larger than the sum of its proper divisors (4466711).

404002120021 is an equidigital number, since it uses as much as digits as its factorization.

404002120021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4466710.

The product of its (nonzero) digits is 128, while the sum is 16.

Adding to 404002120021 its reverse (120021200404), we get a palindrome (524023320425).

The spelling of 404002120021 in words is "four hundred four billion, two million, one hundred twenty thousand, twenty-one".