20523005221 has 4 divisors (see below), whose sum is σ = 20556485452. Its totient is φ = 20489524992.

The previous prime is 20523005219. The next prime is 20523005297. The reversal of 20523005221 is 12250032502.

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 2498600196 + 18024405025 = 49986^2 + 134255^2 .

It is a cyclic number.

It is not a de Polignac number, because 20523005221 - 2¹ = 20523005219 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20523005192 and 20523005201.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20523006221) 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, 16739196 + ... + 16740421.

It is an arithmetic number, because the mean of its divisors is an integer number (5139121363).

Almost surely, 2^20523005221 is an apocalyptic number.

It is an amenable number.

20523005221 is a deficient number, since it is larger than the sum of its proper divisors (33480231).

20523005221 is an equidigital number, since it uses as much as digits as its factorization.

20523005221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33480230.

The product of its (nonzero) digits is 1200, while the sum is 22.

Adding to 20523005221 its reverse (12250032502), we get a palindrome (32773037723).

The spelling of 20523005221 in words is "twenty billion, five hundred twenty-three million, five thousand, two hundred twenty-one".