21221022100121 has 4 divisors (see below), whose sum is σ = 21738608005044. Its totient is φ = 20703436195200.

The previous prime is 21221022100097. The next prime is 21221022100153. The reversal of 21221022100121 is 12100122012212.

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 12018778509721 + 9202243590400 = 3466811^2 + 3033520^2 .

It is a cyclic number.

It is not a de Polignac number, because 21221022100121 - 2²² = 21221017905817 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 21221022100121.

It is not an unprimeable number, because it can be changed into a prime (21221022100181) 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, 258792952400 + ... + 258792952481.

It is an arithmetic number, because the mean of its divisors is an integer number (5434652001261).

Almost surely, 2^{21221022100121} is an apocalyptic number.

It is an amenable number.

21221022100121 is a deficient number, since it is larger than the sum of its proper divisors (517585904923).

21221022100121 is an equidigital number, since it uses as much as digits as its factorization.

21221022100121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 517585904922.

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

Adding to 21221022100121 its reverse (12100122012212), we get a palindrome (33321144112333).

The spelling of 21221022100121 in words is "twenty-one trillion, two hundred twenty-one billion, twenty-two million, one hundred thousand, one hundred twenty-one".