21201210022121 has 16 divisors (see below), whose sum is σ = 22377693916800. Its totient is φ = 20030809189248.

The previous prime is 21201210022099. The next prime is 21201210022127. The reversal of 21201210022121 is 12122001210212.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21201210022121 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21201210022121.

It is not an unprimeable number, because it can be changed into a prime (21201210022127) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 38292500 + ... + 38842218.

It is an arithmetic number, because the mean of its divisors is an integer number (1398605869800).

Almost surely, 2^{21201210022121} is an apocalyptic number.

It is an amenable number.

21201210022121 is a deficient number, since it is larger than the sum of its proper divisors (1176483894679).

21201210022121 is a wasteful number, since it uses less digits than its factorization.

21201210022121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 555248.

The product of its (nonzero) digits is 64, while the sum is 17.

Adding to 21201210022121 its reverse (12122001210212), we get a palindrome (33323211232333).

The spelling of 21201210022121 in words is "twenty-one trillion, two hundred one billion, two hundred ten million, twenty-two thousand, one hundred twenty-one".