21589613666 has 16 divisors (see below), whose sum is σ = 32689198080. Its totient is φ = 10693473840.

The previous prime is 21589613659. The next prime is 21589613707. The reversal of 21589613666 is 66631698512.

It is a happy number.

It is a super-2 number, since 2×21589613666² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 102896 + ... + 231876.

It is an arithmetic number, because the mean of its divisors is an integer number (2043074880).

Almost surely, 2^21589613666 is an apocalyptic number.

21589613666 is a deficient number, since it is larger than the sum of its proper divisors (11099584414).

21589613666 is a wasteful number, since it uses less digits than its factorization.

21589613666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 129769.

The product of its digits is 2799360, while the sum is 53.

The spelling of 21589613666 in words is "twenty-one billion, five hundred eighty-nine million, six hundred thirteen thousand, six hundred sixty-six".