21135135 has 16 divisors (see below), whose sum is σ = 38647296. Its totient is φ = 9661728.

The previous prime is 21135119. The next prime is 21135143. The reversal of 21135135 is 53153112.

It is not a de Polignac number, because 21135135 - 2⁴ = 21135119 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 100539 + ... + 100748.

It is an arithmetic number, because the mean of its divisors is an integer number (2415456).

Almost surely, 2^21135135 is an apocalyptic number.

21135135 is a deficient number, since it is larger than the sum of its proper divisors (17512161).

21135135 is a wasteful number, since it uses less digits than its factorization.

21135135 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 201302.

The product of its digits is 450, while the sum is 21.

The square root of 21135135 is about 4597.2964881548. The cubic root of 21135135 is about 276.4829420047.

Adding to 21135135 its reverse (53153112), we get a palindrome (74288247).

The spelling of 21135135 in words is "twenty-one million, one hundred thirty-five thousand, one hundred thirty-five".