21440424321221 has 8 divisors (see below), whose sum is σ = 21490226847000. Its totient is φ = 21390630912000.

The previous prime is 21440424321167. The next prime is 21440424321259. The reversal of 21440424321221 is 12212342404412.

It can be written as a sum of positive squares in 4 ways, for example, as 4907824360321 + 16532599960900 = 2215361^2 + 4066030^2 .

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21440424321221 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 (21440424321521) 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, 2441285 + ... + 6988613.

It is an arithmetic number, because the mean of its divisors is an integer number (2686278355875).

Almost surely, 2^{21440424321221} is an apocalyptic number.

It is an amenable number.

21440424321221 is a deficient number, since it is larger than the sum of its proper divisors (49802525779).

21440424321221 is a wasteful number, since it uses less digits than its factorization.

21440424321221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4558279.

The product of its (nonzero) digits is 24576, while the sum is 32.

Adding to 21440424321221 its reverse (12212342404412), we get a palindrome (33652766725633).

The spelling of 21440424321221 in words is "twenty-one trillion, four hundred forty billion, four hundred twenty-four million, three hundred twenty-one thousand, two hundred twenty-one".