21118133 has 2 divisors, whose sum is σ = 21118134. Its totient is φ = 21118132.

The previous prime is 21118129. The next prime is 21118147. The reversal of 21118133 is 33181112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21003889 + 114244 = 4583^2 + 338^2 .

It is a cyclic number.

It is not a de Polignac number, because 21118133 - 2² = 21118129 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21118103) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10559066 + 10559067.

It is an arithmetic number, because the mean of its divisors is an integer number (10559067).

Almost surely, 2^21118133 is an apocalyptic number.

It is an amenable number.

21118133 is a deficient number, since it is larger than the sum of its proper divisors (1).

21118133 is an equidigital number, since it uses as much as digits as its factorization.

21118133 is an evil number, because the sum of its binary digits is even.

The product of its digits is 144, while the sum is 20.

The square root of 21118133 is about 4595.4469858763. The cubic root of 21118133 is about 276.4087839098.

Adding to 21118133 its reverse (33181112), we get a palindrome (54299245).

The spelling of 21118133 in words is "twenty-one million, one hundred eighteen thousand, one hundred thirty-three".