21105133 has 16 divisors (see below), whose sum is σ = 25292800. Its totient is φ = 17590608.

The previous prime is 21105121. The next prime is 21105169. The reversal of 21105133 is 33150112.

It is not a de Polignac number, because 21105133 - 2¹³ = 21096941 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 (21105233) 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 15 ways as a sum of consecutive naturals, for example, 11860 + ... + 13522.

It is an arithmetic number, because the mean of its divisors is an integer number (1580800).

Almost surely, 2^21105133 is an apocalyptic number.

It is an amenable number.

21105133 is a deficient number, since it is larger than the sum of its proper divisors (4187667).

21105133 is an equidigital number, since it uses as much as digits as its factorization.

21105133 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1721 (or 1707 counting only the distinct ones).

The product of its (nonzero) digits is 90, while the sum is 16.

The square root of 21105133 is about 4594.0323246577. The cubic root of 21105133 is about 276.3520545930.

Adding to 21105133 its reverse (33150112), we get a palindrome (54255245).

The spelling of 21105133 in words is "twenty-one million, one hundred five thousand, one hundred thirty-three".