21660727222221 has 32 divisors (see below), whose sum is σ = 30053123739648. Its totient is φ = 13866046159680.

The previous prime is 21660727222181. The next prime is 21660727222223. The reversal of 21660727222221 is 12222272706612.

It is not a de Polignac number, because 21660727222221 - 2¹⁰ = 21660727221197 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21660727222223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 318099040 + ... + 318167126.

It is an arithmetic number, because the mean of its divisors is an integer number (939160116864).

Almost surely, 2^{21660727222221} is an apocalyptic number.

It is an amenable number.

21660727222221 is a deficient number, since it is larger than the sum of its proper divisors (8392396517427).

21660727222221 is a wasteful number, since it uses less digits than its factorization.

21660727222221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 110761.

The product of its (nonzero) digits is 225792, while the sum is 42.

Adding to 21660727222221 its reverse (12222272706612), we get a palindrome (33882999928833).

The spelling of 21660727222221 in words is "twenty-one trillion, six hundred sixty billion, seven hundred twenty-seven million, two hundred twenty-two thousand, two hundred twenty-one".