20404241021 has 2 divisors, whose sum is σ = 20404241022. Its totient is φ = 20404241020.

The previous prime is 20404240979. The next prime is 20404241057. The reversal of 20404241021 is 12014240402.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14402640121 + 6001600900 = 120011^2 + 77470^2 .

It is a cyclic number.

It is not a de Polignac number, because 20404241021 - 2⁶ = 20404240957 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20404240984 and 20404241002.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20404241071) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10202120510 + 10202120511.

It is an arithmetic number, because the mean of its divisors is an integer number (10202120511).

Almost surely, 2^20404241021 is an apocalyptic number.

It is an amenable number.

20404241021 is a deficient number, since it is larger than the sum of its proper divisors (1).

20404241021 is an equidigital number, since it uses as much as digits as its factorization.

20404241021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 512, while the sum is 20.

Adding to 20404241021 its reverse (12014240402), we get a palindrome (32418481423).

The spelling of 20404241021 in words is "twenty billion, four hundred four million, two hundred forty-one thousand, twenty-one".