21000212120121 has 32 divisors (see below), whose sum is σ = 30656060803200. Its totient is φ = 12708207936000.

The previous prime is 21000212120023. The next prime is 21000212120141. The reversal of 21000212120121 is 12102121200012.

It is not a de Polignac number, because 21000212120121 - 2¹¹ = 21000212118073 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21000212120121.

It is not an unprimeable number, because it can be changed into a prime (21000212120141) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 8547805 + ... + 10726853.

It is an arithmetic number, because the mean of its divisors is an integer number (958001900100).

Almost surely, 2^{21000212120121} is an apocalyptic number.

It is an amenable number.

21000212120121 is a deficient number, since it is larger than the sum of its proper divisors (9655848683079).

21000212120121 is a wasteful number, since it uses less digits than its factorization.

21000212120121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2183177.

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 21000212120121 its reverse (12102121200012), we get a palindrome (33102333320133).

The spelling of 21000212120121 in words is "twenty-one trillion, two hundred twelve million, one hundred twenty thousand, one hundred twenty-one".