20321321021 has 2 divisors, whose sum is σ = 20321321022. Its totient is φ = 20321321020.

The previous prime is 20321321017. The next prime is 20321321101. The reversal of 20321321021 is 12012312302.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19568092996 + 753228025 = 139886^2 + 27445^2 .

It is a cyclic number.

It is not a de Polignac number, because 20321321021 - 2² = 20321321017 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20321321621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10160660510 + 10160660511.

It is an arithmetic number, because the mean of its divisors is an integer number (10160660511).

Almost surely, 2^20321321021 is an apocalyptic number.

It is an amenable number.

20321321021 is a deficient number, since it is larger than the sum of its proper divisors (1).

20321321021 is an equidigital number, since it uses as much as digits as its factorization.

20321321021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 144, while the sum is 17.

Adding to 20321321021 its reverse (12012312302), we get a palindrome (32333633323).

The spelling of 20321321021 in words is "twenty billion, three hundred twenty-one million, three hundred twenty-one thousand, twenty-one".