21666980873 has 8 divisors (see below), whose sum is σ = 21780112200. Its totient is φ = 21554011008.

The previous prime is 21666980833. The next prime is 21666980891. The reversal of 21666980873 is 37808966612.

It can be written as a sum of positive squares in 4 ways, for example, as 13123306249 + 8543674624 = 114557^2 + 92432^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 21666980873 - 2¹⁰ = 21666979849 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21666980833) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 233543 + ... + 312851.

It is an arithmetic number, because the mean of its divisors is an integer number (2722514025).

Almost surely, 2^21666980873 is an apocalyptic number.

It is an amenable number.

21666980873 is a deficient number, since it is larger than the sum of its proper divisors (113131327).

21666980873 is a wasteful number, since it uses less digits than its factorization.

21666980873 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80731.

The product of its (nonzero) digits is 5225472, while the sum is 56.

The spelling of 21666980873 in words is "twenty-one billion, six hundred sixty-six million, nine hundred eighty thousand, eight hundred seventy-three".