21606172206 has 8 divisors (see below), whose sum is σ = 43212344424. Its totient is φ = 7202057400.

The previous prime is 21606172187. The next prime is 21606172241. The reversal of 21606172206 is 60227160612.

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

21606172206 is an admirable number.

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1800514345 + ... + 1800514356.

It is an arithmetic number, because the mean of its divisors is an integer number (5401543053).

Almost surely, 2^21606172206 is an apocalyptic number.

21606172206 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21606172206 is a wasteful number, since it uses less digits than its factorization.

21606172206 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3601028706.

The product of its (nonzero) digits is 12096, while the sum is 33.

The spelling of 21606172206 in words is "twenty-one billion, six hundred six million, one hundred seventy-two thousand, two hundred six".