21660540425305 has 4 divisors (see below), whose sum is σ = 25992648510372. Its totient is φ = 17328432340240.

The previous prime is 21660540425287. The next prime is 21660540425399. The reversal of 21660540425305 is 50352404506612.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 6671625536601 + 14988914888704 = 2582949^2 + 3871552^2 .

It is not a de Polignac number, because 21660540425305 - 2¹¹ = 21660540423257 is a prime.

It is a super-2 number, since 2×21660540425305² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 2166054042526 + ... + 2166054042535.

It is an arithmetic number, because the mean of its divisors is an integer number (6498162127593).

Almost surely, 2^{21660540425305} is an apocalyptic number.

It is an amenable number.

21660540425305 is a deficient number, since it is larger than the sum of its proper divisors (4332108085067).

21660540425305 is an equidigital number, since it uses as much as digits as its factorization.

21660540425305 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4332108085066.

The product of its (nonzero) digits is 864000, while the sum is 43.

The spelling of 21660540425305 in words is "twenty-one trillion, six hundred sixty billion, five hundred forty million, four hundred twenty-five thousand, three hundred five".