21200101222121 has 4 divisors (see below), whose sum is σ = 21200127311700. Its totient is φ = 21200075132544.

The previous prime is 21200101222081. The next prime is 21200101222147. The reversal of 21200101222121 is 12122210100212.

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 11440325346025 + 9759775876096 = 3382355^2 + 3124064^2 .

It is a cyclic number.

It is not a de Polignac number, because 21200101222121 - 2⁶ = 21200101222057 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 21200101222121.

It is not an unprimeable number, because it can be changed into a prime (21200101222151) 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, 11785376 + ... + 13464593.

It is an arithmetic number, because the mean of its divisors is an integer number (5300031827925).

Almost surely, 2^{21200101222121} is an apocalyptic number.

It is an amenable number.

21200101222121 is a deficient number, since it is larger than the sum of its proper divisors (26089579).

21200101222121 is an equidigital number, since it uses as much as digits as its factorization.

21200101222121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26089578.

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

Adding to 21200101222121 its reverse (12122210100212), we get a palindrome (33322311322333).

The spelling of 21200101222121 in words is "twenty-one trillion, two hundred billion, one hundred one million, two hundred twenty-two thousand, one hundred twenty-one".