21666737279744 has 144 divisors (see below), whose sum is σ = 47292588677376. Its totient is φ = 9862506086400.

The previous prime is 21666737279689. The next prime is 21666737279791. The reversal of 21666737279744 is 44797273766612.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 291507674 + ... + 291581990.

It is an arithmetic number, because the mean of its divisors is an integer number (328420754704).

Almost surely, 2^{21666737279744} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21666737279744, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23646294338688).

21666737279744 is an abundant number, since it is smaller than the sum of its proper divisors (25625851397632).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21666737279744 is a wasteful number, since it uses less digits than its factorization.

21666737279744 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 76542 (or 76528 counting only the distinct ones).

The product of its digits is 896168448, while the sum is 71.

The spelling of 21666737279744 in words is "twenty-one trillion, six hundred sixty-six billion, seven hundred thirty-seven million, two hundred seventy-nine thousand, seven hundred forty-four".