21666517336 has 16 divisors (see below), whose sum is σ = 41196900240. Its totient is φ = 10680677280.

The previous prime is 21666517321. The next prime is 21666517337. The reversal of 21666517336 is 63371566612.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21666517337) 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, 19072071 + ... + 19073206.

It is an arithmetic number, because the mean of its divisors is an integer number (2574806265).

Almost surely, 2^21666517336 is an apocalyptic number.

It is an amenable number.

21666517336 is a deficient number, since it is larger than the sum of its proper divisors (19530382904).

21666517336 is a wasteful number, since it uses less digits than its factorization.

21666517336 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38145354 (or 38145350 counting only the distinct ones).

The product of its digits is 816480, while the sum is 46.

The spelling of 21666517336 in words is "twenty-one billion, six hundred sixty-six million, five hundred seventeen thousand, three hundred thirty-six".