21660550689 has 16 divisors (see below), whose sum is σ = 29943216000. Its totient is φ = 13911346176.

The previous prime is 21660550673. The next prime is 21660550699. The reversal of 21660550689 is 98605506612.

It is not a de Polignac number, because 21660550689 - 2⁴ = 21660550673 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21660550699) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 238189 + ... + 316314.

It is an arithmetic number, because the mean of its divisors is an integer number (1871451000).

Almost surely, 2^21660550689 is an apocalyptic number.

21660550689 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

It is an amenable number.

21660550689 is a deficient number, since it is larger than the sum of its proper divisors (8282665311).

21660550689 is a wasteful number, since it uses less digits than its factorization.

21660550689 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 554984.

The product of its (nonzero) digits is 777600, while the sum is 48.

The spelling of 21660550689 in words is "twenty-one billion, six hundred sixty million, five hundred fifty thousand, six hundred eighty-nine".