21544423340221 has 8 divisors (see below), whose sum is σ = 22815226782720. Its totient is φ = 20274007055808.

The previous prime is 21544423340191. The next prime is 21544423340311. The reversal of 21544423340221 is 12204332444512.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21544423340221 - 2⁹ = 21544423339709 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21544423340021) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 96674941 + ... + 96897538.

It is an arithmetic number, because the mean of its divisors is an integer number (2851903347840).

Almost surely, 2^{21544423340221} is an apocalyptic number.

It is an amenable number.

21544423340221 is a deficient number, since it is larger than the sum of its proper divisors (1270803442499).

21544423340221 is a wasteful number, since it uses less digits than its factorization.

21544423340221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 193579043.

The product of its (nonzero) digits is 184320, while the sum is 37.

Adding to 21544423340221 its reverse (12204332444512), we get a palindrome (33748755784733).

The spelling of 21544423340221 in words is "twenty-one trillion, five hundred forty-four billion, four hundred twenty-three million, three hundred forty thousand, two hundred twenty-one".