21001133 has 8 divisors (see below), whose sum is σ = 21778200. Its totient is φ = 20227648.

The previous prime is 21001121. The next prime is 21001153. The reversal of 21001133 is 33110012.

It can be written as a sum of positive squares in 4 ways, for example, as 88804 + 20912329 = 298^2 + 4573^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 21001133 - 2⁴ = 21001117 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21001153) 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, 18383 + ... + 19491.

It is an arithmetic number, because the mean of its divisors is an integer number (2722275).

Almost surely, 2^21001133 is an apocalyptic number.

It is an amenable number.

21001133 is a deficient number, since it is larger than the sum of its proper divisors (777067).

21001133 is a wasteful number, since it uses less digits than its factorization.

21001133 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1791.

The product of its (nonzero) digits is 18, while the sum is 11.

The square root of 21001133 is about 4582.6993137233. The cubic root of 21001133 is about 275.8973792332.

Adding to 21001133 its reverse (33110012), we get a palindrome (54111145).

The spelling of 21001133 in words is "twenty-one million, one thousand, one hundred thirty-three".