21202101220121 has 4 divisors (see below), whose sum is σ = 22449283644852. Its totient is φ = 19954918795392.

The previous prime is 21202101220061. The next prime is 21202101220211. The reversal of 21202101220121 is 12102210120212.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 15682590015625 + 5519511204496 = 3960125^2 + 2349364^2 .

It is a cyclic number.

It is not a de Polignac number, because 21202101220121 - 2³⁸ = 20927223313177 is a prime.

It is a super-2 number, since 2×21202101220121² (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (17), and also a Moran number because the ratio is a prime number: 1247182424713 = 21202101220121 / (2 + 1 + 2 + 0 + 2 + 1 + 0 + 1 + 2 + 2 + 0 + 1 + 2 + 1).

It is a self number, because there is not a number n which added to its sum of digits gives 21202101220121.

It is not an unprimeable number, because it can be changed into a prime (21202100220121) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 623591212340 + ... + 623591212373.

It is an arithmetic number, because the mean of its divisors is an integer number (5612320911213).

Almost surely, 2^{21202101220121} is an apocalyptic number.

It is an amenable number.

21202101220121 is a deficient number, since it is larger than the sum of its proper divisors (1247182424731).

21202101220121 is a wasteful number, since it uses less digits than its factorization.

21202101220121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1247182424730.

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

Adding to 21202101220121 its reverse (12102210120212), we get a palindrome (33304311340333).

The spelling of 21202101220121 in words is "twenty-one trillion, two hundred two billion, one hundred one million, two hundred twenty thousand, one hundred twenty-one".