21660354631121 has 8 divisors (see below), whose sum is σ = 23015533755744. Its totient is φ = 20314180019520.

The previous prime is 21660354631109. The next prime is 21660354631129. The reversal of 21660354631121 is 12113645306612.

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 21660354631121 - 2¹⁸ = 21660354368977 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21660354631129) 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, 2251123295 + ... + 2251132916.

It is an arithmetic number, because the mean of its divisors is an integer number (2876941719468).

Almost surely, 2^{21660354631121} is an apocalyptic number.

It is an amenable number.

21660354631121 is a deficient number, since it is larger than the sum of its proper divisors (1355179124623).

21660354631121 is a wasteful number, since it uses less digits than its factorization.

21660354631121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4502256511.

The product of its (nonzero) digits is 155520, while the sum is 41.

Adding to 21660354631121 its reverse (12113645306612), we get a palindrome (33773999937733).

The spelling of 21660354631121 in words is "twenty-one trillion, six hundred sixty billion, three hundred fifty-four million, six hundred thirty-one thousand, one hundred twenty-one".