21530123221201 has 4 divisors (see below), whose sum is σ = 24605855109952. Its totient is φ = 18454391332452.

The previous prime is 21530123221199. The next prime is 21530123221207. The reversal of 21530123221201 is 10212232103512.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21530123221201 - 2¹ = 21530123221199 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21530123221207) 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, 1537865944365 + ... + 1537865944378.

It is an arithmetic number, because the mean of its divisors is an integer number (6151463777488).

Almost surely, 2^{21530123221201} is an apocalyptic number.

It is an amenable number.

21530123221201 is a deficient number, since it is larger than the sum of its proper divisors (3075731888751).

21530123221201 is an equidigital number, since it uses as much as digits as its factorization.

21530123221201 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3075731888750.

The product of its (nonzero) digits is 1440, while the sum is 25.

Adding to 21530123221201 its reverse (10212232103512), we get a palindrome (31742355324713).

The spelling of 21530123221201 in words is "twenty-one trillion, five hundred thirty billion, one hundred twenty-three million, two hundred twenty-one thousand, two hundred one".