21216236221064 has 16 divisors (see below), whose sum is σ = 39780550036620. Its totient is φ = 10608089544640.

The previous prime is 21216236221039. The next prime is 21216236221163. The reversal of 21216236221064 is 46012263261212.

It can be written as a sum of positive squares in 2 ways, for example, as 21201512340100 + 14723880964 = 4604510^2 + 121342^2 .

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, 230399 + ... + 6518094.

Almost surely, 2^{21216236221064} is an apocalyptic number.

It is an amenable number.

21216236221064 is a deficient number, since it is larger than the sum of its proper divisors (18564313815556).

21216236221064 is a wasteful number, since it uses less digits than its factorization.

21216236221064 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7141480 (or 7141476 counting only the distinct ones).

The product of its (nonzero) digits is 82944, while the sum is 38.

Adding to 21216236221064 its reverse (46012263261212), we get a palindrome (67228499482276).

The spelling of 21216236221064 in words is "twenty-one trillion, two hundred sixteen billion, two hundred thirty-six million, two hundred twenty-one thousand, sixty-four".