21145133 has 4 divisors (see below), whose sum is σ = 21460800. Its totient is φ = 20829468.

The previous prime is 21145109. The next prime is 21145141. The reversal of 21145133 is 33154112.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21145133 - 2¹² = 21141037 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21145183) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 157733 + ... + 157866.

It is an arithmetic number, because the mean of its divisors is an integer number (5365200).

Almost surely, 2^21145133 is an apocalyptic number.

It is an amenable number.

21145133 is a deficient number, since it is larger than the sum of its proper divisors (315667).

21145133 is an equidigital number, since it uses as much as digits as its factorization.

21145133 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 315666.

The product of its digits is 360, while the sum is 20.

The square root of 21145133 is about 4598.3837377931. The cubic root of 21145133 is about 276.5265319903.

Adding to 21145133 its reverse (33154112), we get a palindrome (54299245).

The spelling of 21145133 in words is "twenty-one million, one hundred forty-five thousand, one hundred thirty-three".