21000133021121 has 8 divisors (see below), whose sum is σ = 21575945668200. Its totient is φ = 20424754136448.

The previous prime is 21000133021093. The next prime is 21000133021201. The reversal of 21000133021121 is 12112033100012.

It can be written as a sum of positive squares in 4 ways, for example, as 10482668913025 + 10517464108096 = 3237695^2 + 3243064^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21000133021121 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21000133021121.

It is not an unprimeable number, because it can be changed into a prime (21000133020121) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 108342446 + ... + 108536103.

It is an arithmetic number, because the mean of its divisors is an integer number (2696993208525).

Almost surely, 2^{21000133021121} is an apocalyptic number.

It is an amenable number.

21000133021121 is a deficient number, since it is larger than the sum of its proper divisors (575812647079).

21000133021121 is a wasteful number, since it uses less digits than its factorization.

21000133021121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 216881203.

The product of its (nonzero) digits is 72, while the sum is 17.

Adding to 21000133021121 its reverse (12112033100012), we get a palindrome (33112166121133).

The spelling of 21000133021121 in words is "twenty-one trillion, one hundred thirty-three million, twenty-one thousand, one hundred twenty-one".