21288135 has 48 divisors (see below), whose sum is σ = 38572128. Its totient is φ = 10010880.

The previous prime is 21288119. The next prime is 21288161. The reversal of 21288135 is 53188212.

It is not a de Polignac number, because 21288135 - 2⁴ = 21288119 is a prime.

21288135 is a Rhonda number in base 10.

Its product of digits (3840) is a multiple of the sum of its prime factors (384).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 66997 + ... + 67313.

It is an arithmetic number, because the mean of its divisors is an integer number (803586).

Almost surely, 2^21288135 is an apocalyptic number.

21288135 is a deficient number, since it is larger than the sum of its proper divisors (17283993).

21288135 is a wasteful number, since it uses less digits than its factorization.

21288135 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 384 (or 373 counting only the distinct ones).

The product of its digits is 3840, while the sum is 30.

The square root of 21288135 is about 4613.9066960657. The cubic root of 21288135 is about 277.1485039135.

The spelling of 21288135 in words is "twenty-one million, two hundred eighty-eight thousand, one hundred thirty-five".