20321075521 has 4 divisors (see below), whose sum is σ = 20321455572. Its totient is φ = 20320695472.

The previous prime is 20321075519. The next prime is 20321075527. The reversal of 20321075521 is 12557012302.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 8637843600 + 11683231921 = 92940^2 + 108089^2 .

It is a cyclic number.

It is not a de Polignac number, because 20321075521 - 2¹ = 20321075519 is a prime.

It is a super-2 number, since 2×20321075521² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20321075521.

It is not an unprimeable number, because it can be changed into a prime (20321075527) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 93466 + ... + 222211.

It is an arithmetic number, because the mean of its divisors is an integer number (5080363893).

Almost surely, 2^20321075521 is an apocalyptic number.

It is an amenable number.

20321075521 is a deficient number, since it is larger than the sum of its proper divisors (380051).

20321075521 is an equidigital number, since it uses as much as digits as its factorization.

20321075521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 380050.

The product of its (nonzero) digits is 4200, while the sum is 28.

Adding to 20321075521 its reverse (12557012302), we get a palindrome (32878087823).

The spelling of 20321075521 in words is "twenty billion, three hundred twenty-one million, seventy-five thousand, five hundred twenty-one".