21666737279747 has 8 divisors (see below), whose sum is σ = 24763492439136. Its totient is φ = 18570358864512.

The previous prime is 21666737279689. The next prime is 21666737279791. The reversal of 21666737279747 is 74797273766612.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21666737279747 - 2⁶ = 21666737279683 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21666737279647) 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, 94062788 + ... + 94292849.

It is an arithmetic number, because the mean of its divisors is an integer number (3095436554892).

Almost surely, 2^{21666737279747} is an apocalyptic number.

21666737279747 is a deficient number, since it is larger than the sum of its proper divisors (3096755159389).

21666737279747 is a wasteful number, since it uses less digits than its factorization.

21666737279747 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 188372077.

The product of its digits is 1568294784, while the sum is 74.

The spelling of 21666737279747 in words is "twenty-one trillion, six hundred sixty-six billion, seven hundred thirty-seven million, two hundred seventy-nine thousand, seven hundred forty-seven".