20404334021 has 2 divisors, whose sum is σ = 20404334022. Its totient is φ = 20404334020.

The previous prime is 20404333991. The next prime is 20404334059. The reversal of 20404334021 is 12043340402.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18404992225 + 1999341796 = 135665^2 + 44714^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20404334021 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20404334081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10202167010 + 10202167011.

It is an arithmetic number, because the mean of its divisors is an integer number (10202167011).

Almost surely, 2^20404334021 is an apocalyptic number.

It is an amenable number.

20404334021 is a deficient number, since it is larger than the sum of its proper divisors (1).

20404334021 is an equidigital number, since it uses as much as digits as its factorization.

20404334021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2304, while the sum is 23.

Adding to 20404334021 its reverse (12043340402), we get a palindrome (32447674423).

The spelling of 20404334021 in words is "twenty billion, four hundred four million, three hundred thirty-four thousand, twenty-one".