20320355521 has 2 divisors, whose sum is σ = 20320355522. Its totient is φ = 20320355520.

The previous prime is 20320355519. The next prime is 20320355557. The reversal of 20320355521 is 12555302302.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10844306496 + 9476049025 = 104136^2 + 97345^2 .

It is a cyclic number.

It is not a de Polignac number, because 20320355521 - 2¹ = 20320355519 is a prime.

Together with 20320355519, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 20320355521.

It is not a weakly prime, because it can be changed into another prime (20320350521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10160177760 + 10160177761.

It is an arithmetic number, because the mean of its divisors is an integer number (10160177761).

Almost surely, 2^20320355521 is an apocalyptic number.

It is an amenable number.

20320355521 is a deficient number, since it is larger than the sum of its proper divisors (1).

20320355521 is an equidigital number, since it uses as much as digits as its factorization.

20320355521 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 9000, while the sum is 28.

Adding to 20320355521 its reverse (12555302302), we get a palindrome (32875657823).

The spelling of 20320355521 in words is "twenty billion, three hundred twenty million, three hundred fifty-five thousand, five hundred twenty-one".