20420321334221 has 2 divisors, whose sum is σ = 20420321334222. Its totient is φ = 20420321334220.

The previous prime is 20420321334173. The next prime is 20420321334263. The reversal of 20420321334221 is 12243312302402.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17911423731721 + 2508897602500 = 4232189^2 + 1583950^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20420321334221 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20420321334121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10210160667110 + 10210160667111.

It is an arithmetic number, because the mean of its divisors is an integer number (10210160667111).

Almost surely, 2^{20420321334221} is an apocalyptic number.

It is an amenable number.

20420321334221 is a deficient number, since it is larger than the sum of its proper divisors (1).

20420321334221 is an equidigital number, since it uses as much as digits as its factorization.

20420321334221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 13824, while the sum is 29.

Adding to 20420321334221 its reverse (12243312302402), we get a palindrome (32663633636623).

The spelling of 20420321334221 in words is "twenty trillion, four hundred twenty billion, three hundred twenty-one million, three hundred thirty-four thousand, two hundred twenty-one".