21355332423321 has 16 divisors (see below), whose sum is σ = 30665489423744. Its totient is φ = 13141133449344.

The previous prime is 21355332423307. The next prime is 21355332423329. The reversal of 21355332423321 is 12332423355312.

It is a happy number.

It is not a de Polignac number, because 21355332423321 - 2¹⁷ = 21355332292249 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21355332423321.

It is not an unprimeable number, because it can be changed into a prime (21355332423329) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11847301 + ... + 13530306.

It is an arithmetic number, because the mean of its divisors is an integer number (1916593088984).

Almost surely, 2^{21355332423321} is an apocalyptic number.

It is an amenable number.

21355332423321 is a deficient number, since it is larger than the sum of its proper divisors (9310157000423).

21355332423321 is a wasteful number, since it uses less digits than its factorization.

21355332423321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25399200.

The product of its digits is 388800, while the sum is 39.

Adding to 21355332423321 its reverse (12332423355312), we get a palindrome (33687755778633).

The spelling of 21355332423321 in words is "twenty-one trillion, three hundred fifty-five billion, three hundred thirty-two million, four hundred twenty-three thousand, three hundred twenty-one".