21666267613741 has 4 divisors (see below), whose sum is σ = 21730559209372. Its totient is φ = 21601976018112.

The previous prime is 21666267613703. The next prime is 21666267613747. The reversal of 21666267613741 is 14731676266612.

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 1856735989641 + 19809531624100 = 1362621^2 + 4450790^2 .

It is a cyclic number.

It is not a de Polignac number, because 21666267613741 - 2³⁵ = 21631907875373 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21666267613747) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 32145797310 + ... + 32145797983.

It is an arithmetic number, because the mean of its divisors is an integer number (5432639802343).

Almost surely, 2^{21666267613741} is an apocalyptic number.

It is an amenable number.

21666267613741 is a deficient number, since it is larger than the sum of its proper divisors (64291595631).

21666267613741 is an equidigital number, since it uses as much as digits as its factorization.

21666267613741 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64291595630.

The product of its digits is 18289152, while the sum is 58.

The spelling of 21666267613741 in words is "twenty-one trillion, six hundred sixty-six billion, two hundred sixty-seven million, six hundred thirteen thousand, seven hundred forty-one".