21153135 has 16 divisors (see below), whose sum is σ = 33967584. Its totient is φ = 11240832.

The previous prime is 21153133. The next prime is 21153161. The reversal of 21153135 is 53135112.

It is not a de Polignac number, because 21153135 - 2¹ = 21153133 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21153133) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1989 + ... + 6801.

It is an arithmetic number, because the mean of its divisors is an integer number (2122974).

Almost surely, 2^21153135 is an apocalyptic number.

21153135 is a deficient number, since it is larger than the sum of its proper divisors (12814449).

21153135 is a wasteful number, since it uses less digits than its factorization.

21153135 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5114.

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

The square root of 21153135 is about 4599.2537438154. The cubic root of 21153135 is about 276.5614097758.

Adding to 21153135 its reverse (53135112), we get a palindrome (74288247).

The spelling of 21153135 in words is "twenty-one million, one hundred fifty-three thousand, one hundred thirty-five".