21589409418221 has 8 divisors (see below), whose sum is σ = 21943455221688. Its totient is φ = 21235367520000.

The previous prime is 21589409418197. The next prime is 21589409418223. The reversal of 21589409418221 is 12281490498512.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 6196420326121 + 15392989092100 = 2489261^2 + 3923390^2 .

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 21589409418221 - 2¹⁰ = 21589409417197 is a prime.

It is a super-2 number, since 2×21589409418221² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21589409418223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11459081 + ... + 13209441.

It is an arithmetic number, because the mean of its divisors is an integer number (2742931902711).

Almost surely, 2^{21589409418221} is an apocalyptic number.

It is an amenable number.

21589409418221 is a deficient number, since it is larger than the sum of its proper divisors (354045803467).

21589409418221 is a wasteful number, since it uses less digits than its factorization.

21589409418221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1952623.

The product of its (nonzero) digits is 3317760, while the sum is 56.

The spelling of 21589409418221 in words is "twenty-one trillion, five hundred eighty-nine billion, four hundred nine million, four hundred eighteen thousand, two hundred twenty-one".