21201221121212 has 48 divisors (see below), whose sum is σ = 41279018256000. Its totient is φ = 9446435751360.

The previous prime is 21201221121193. The next prime is 21201221121221. The reversal of 21201221121212 is 21212112210212.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10794398 + ... + 12606405.

It is an arithmetic number, because the mean of its divisors is an integer number (859979547000).

Almost surely, 2^{21201221121212} is an apocalyptic number.

21201221121212 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21201221121212 is a deficient number, since it is larger than the sum of its proper divisors (20077797134788).

21201221121212 is a wasteful number, since it uses less digits than its factorization.

21201221121212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23401226 (or 23401224 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 20.

Adding to 21201221121212 its reverse (21212112210212), we get a palindrome (42413333331424).

The spelling of 21201221121212 in words is "twenty-one trillion, two hundred one billion, two hundred twenty-one million, one hundred twenty-one thousand, two hundred twelve".