21210102202121 has 32 divisors (see below), whose sum is σ = 26365081754880. Its totient is φ = 16647716929536.

The previous prime is 21210102202063. The next prime is 21210102202181. The reversal of 21210102202121 is 12120220101212.

It is not a de Polignac number, because 21210102202121 - 2³⁰ = 21209028460297 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (17).

It is a self number, because there is not a number n which added to its sum of digits gives 21210102202121.

It is not an unprimeable number, because it can be changed into a prime (21210102202181) 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, 6749186 + ... + 9379323.

It is an arithmetic number, because the mean of its divisors is an integer number (823908804840).

Almost surely, 2^{21210102202121} is an apocalyptic number.

It is an amenable number.

21210102202121 is a deficient number, since it is larger than the sum of its proper divisors (5154979552759).

21210102202121 is a wasteful number, since it uses less digits than its factorization.

21210102202121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16128833.

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

Adding to 21210102202121 its reverse (12120220101212), we get a palindrome (33330322303333).

The spelling of 21210102202121 in words is "twenty-one trillion, two hundred ten billion, one hundred two million, two hundred two thousand, one hundred twenty-one".