21135105 has 24 divisors (see below), whose sum is σ = 36840960. Its totient is φ = 11208480.

The previous prime is 21135073. The next prime is 21135109. The reversal of 21135105 is 50153112.

It is not a de Polignac number, because 21135105 - 2⁵ = 21135073 is a prime.

It is a super-2 number, since 2×21135105² = 893385326722050, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21135109) 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 23 ways as a sum of consecutive naturals, for example, 7366 + ... + 9824.

It is an arithmetic number, because the mean of its divisors is an integer number (1535040).

Almost surely, 2^21135105 is an apocalyptic number.

It is an amenable number.

21135105 is a deficient number, since it is larger than the sum of its proper divisors (15705855).

21135105 is a wasteful number, since it uses less digits than its factorization.

21135105 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2661 (or 2658 counting only the distinct ones).

The product of its (nonzero) digits is 150, while the sum is 18.

The square root of 21135105 is about 4597.2932253664. The cubic root of 21135105 is about 276.4828111879.

Adding to 21135105 its reverse (50153112), we get a palindrome (71288217).

The spelling of 21135105 in words is "twenty-one million, one hundred thirty-five thousand, one hundred five".