21164360066 has 4 divisors (see below), whose sum is σ = 31746540102. Its totient is φ = 10582180032.

The previous prime is 21164360059. The next prime is 21164360089. The reversal of 21164360066 is 66006346112.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 12809486041 + 8354874025 = 113179^2 + 91405^2 .

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 as a sum of consecutive naturals, namely, 5291090015 + ... + 5291090018.

Almost surely, 2^21164360066 is an apocalyptic number.

21164360066 is a deficient number, since it is larger than the sum of its proper divisors (10582180036).

21164360066 is a wasteful number, since it uses less digits than its factorization.

21164360066 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10582180035.

The product of its (nonzero) digits is 31104, while the sum is 35.

The spelling of 21164360066 in words is "twenty-one billion, one hundred sixty-four million, three hundred sixty thousand, sixty-six".