21532423205 has 4 divisors (see below), whose sum is σ = 25838907852. Its totient is φ = 17225938560.

The previous prime is 21532423177. The next prime is 21532423229. The reversal of 21532423205 is 50232423512.

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 15927954436 + 5604468769 = 126206^2 + 74863^2 .

It is not a de Polignac number, because 21532423205 - 2³⁰ = 20458681381 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2153242316 + ... + 2153242325.

It is an arithmetic number, because the mean of its divisors is an integer number (6459726963).

Almost surely, 2^21532423205 is an apocalyptic number.

It is an amenable number.

21532423205 is a deficient number, since it is larger than the sum of its proper divisors (4306484647).

21532423205 is an equidigital number, since it uses as much as digits as its factorization.

21532423205 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4306484646.

The product of its (nonzero) digits is 14400, while the sum is 29.

Adding to 21532423205 its reverse (50232423512), we get a palindrome (71764846717).

The spelling of 21532423205 in words is "twenty-one billion, five hundred thirty-two million, four hundred twenty-three thousand, two hundred five".