21103212133121 has 4 divisors (see below), whose sum is σ = 21103325901012. Its totient is φ = 21103098365232.

The previous prime is 21103212133063. The next prime is 21103212133139. The reversal of 21103212133121 is 12133121230112.

It is a happy number.

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 19650283242496 + 1452928890625 = 4432864^2 + 1205375^2 .

It is a cyclic number.

It is not a de Polignac number, because 21103212133121 - 2³⁰ = 21102138391297 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21103212133321) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 56605250 + ... + 56976843.

It is an arithmetic number, because the mean of its divisors is an integer number (5275831475253).

Almost surely, 2^{21103212133121} is an apocalyptic number.

It is an amenable number.

21103212133121 is a deficient number, since it is larger than the sum of its proper divisors (113767891).

21103212133121 is a wasteful number, since it uses less digits than its factorization.

21103212133121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 113767890.

The product of its (nonzero) digits is 432, while the sum is 23.

Adding to 21103212133121 its reverse (12133121230112), we get a palindrome (33236333363233).

The spelling of 21103212133121 in words is "twenty-one trillion, one hundred three billion, two hundred twelve million, one hundred thirty-three thousand, one hundred twenty-one".