21033021121 has 12 divisors (see below), whose sum is σ = 24802152132. Its totient is φ = 17781337728.

The previous prime is 21033021091. The next prime is 21033021127. The reversal of 21033021121 is 12112033012.

It can be written as a sum of positive squares in 2 ways, for example, as 7112560896 + 13920460225 = 84336^2 + 117985^2 .

It is a de Polignac number, because none of the positive numbers 2^k-21033021121 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21033021095 and 21033021104.

It is not an unprimeable number, because it can be changed into a prime (21033021127) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2936460 + ... + 2943613.

It is an arithmetic number, because the mean of its divisors is an integer number (2066846011).

Almost surely, 2^21033021121 is an apocalyptic number.

It is an amenable number.

21033021121 is a deficient number, since it is larger than the sum of its proper divisors (3769131011).

21033021121 is an equidigital number, since it uses as much as digits as its factorization.

21033021121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5880160 (or 5880153 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 16.

Adding to 21033021121 its reverse (12112033012), we get a palindrome (33145054133).

The spelling of 21033021121 in words is "twenty-one billion, thirty-three million, twenty-one thousand, one hundred twenty-one".