21666608411 has 8 divisors (see below), whose sum is σ = 24765266400. Its totient is φ = 18568807488.

The previous prime is 21666608401. The next prime is 21666608413. The reversal of 21666608411 is 11480666612.

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

It is not a de Polignac number, because 21666608411 - 2⁶ = 21666608347 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21666608413) 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, 159146 + ... + 262031.

It is an arithmetic number, because the mean of its divisors is an integer number (3095658300).

Almost surely, 2^21666608411 is an apocalyptic number.

21666608411 is a deficient number, since it is larger than the sum of its proper divisors (3098657989).

21666608411 is an equidigital number, since it uses as much as digits as its factorization.

21666608411 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 428533.

The product of its (nonzero) digits is 82944, while the sum is 41.

The spelling of 21666608411 in words is "twenty-one billion, six hundred sixty-six million, six hundred eight thousand, four hundred eleven".