21643544606 has 8 divisors (see below), whose sum is σ = 32698880760. Its totient is φ = 10743917688.

The previous prime is 21643544591. The next prime is 21643544623. The reversal of 21643544606 is 60644534612.

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

It is a super-2 number, since 2×21643544606² (a number of 21 digits) contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 38926961 + ... + 38927516.

It is an arithmetic number, because the mean of its divisors is an integer number (4087360095).

Almost surely, 2^21643544606 is an apocalyptic number.

21643544606 is a deficient number, since it is larger than the sum of its proper divisors (11055336154).

21643544606 is a wasteful number, since it uses less digits than its factorization.

21643544606 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 77854618.

The product of its (nonzero) digits is 414720, while the sum is 41.

The spelling of 21643544606 in words is "twenty-one billion, six hundred forty-three million, five hundred forty-four thousand, six hundred six".