20042320021 has 2 divisors, whose sum is σ = 20042320022. Its totient is φ = 20042320020.

The previous prime is 20042320013. The next prime is 20042320057. The reversal of 20042320021 is 12002324002.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10771326225 + 9270993796 = 103785^2 + 96286^2 .

It is a cyclic number.

It is not a de Polignac number, because 20042320021 - 2³ = 20042320013 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20042319977 and 20042320004.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20042320061) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10021160010 + 10021160011.

It is an arithmetic number, because the mean of its divisors is an integer number (10021160011).

Almost surely, 2^20042320021 is an apocalyptic number.

It is an amenable number.

20042320021 is a deficient number, since it is larger than the sum of its proper divisors (1).

20042320021 is an equidigital number, since it uses as much as digits as its factorization.

20042320021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 192, while the sum is 16.

Adding to 20042320021 its reverse (12002324002), we get a palindrome (32044644023).

The spelling of 20042320021 in words is "twenty billion, forty-two million, three hundred twenty thousand, twenty-one".