21212206166206 has 16 divisors (see below), whose sum is σ = 34711447731840. Its totient is φ = 9641754973080.

The previous prime is 21212206166201. The next prime is 21212206166237. The reversal of 21212206166206 is 60266160221212.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21212206166201) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6458076 + ... + 9172303.

It is an arithmetic number, because the mean of its divisors is an integer number (2169465483240).

Almost surely, 2^{21212206166206} is an apocalyptic number.

21212206166206 is a deficient number, since it is larger than the sum of its proper divisors (13499241565634).

21212206166206 is a wasteful number, since it uses less digits than its factorization.

21212206166206 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15692079.

The product of its (nonzero) digits is 41472, while the sum is 37.

Adding to 21212206166206 its reverse (60266160221212), we get a palindrome (81478366387418).

The spelling of 21212206166206 in words is "twenty-one trillion, two hundred twelve billion, two hundred six million, one hundred sixty-six thousand, two hundred six".