21126288 has 20 divisors (see below), whose sum is σ = 54576368. Its totient is φ = 7042080.

The previous prime is 21126253. The next prime is 21126289. The reversal of 21126288 is 88262112.

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (21126289) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 220018 + ... + 220113.

Almost surely, 2^21126288 is an apocalyptic number.

It is an amenable number.

21126288 is an abundant number, since it is smaller than the sum of its proper divisors (33450080).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21126288 is a wasteful number, since it uses less digits than its factorization.

21126288 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 440142 (or 440136 counting only the distinct ones).

The product of its digits is 3072, while the sum is 30.

The square root of 21126288 is about 4596.3341915052. The cubic root of 21126288 is about 276.4443587646. Note that the first 3 decimals are identical.

Subtracting from 21126288 its product of digits (3072), we obtain a square (21123216 = 4596²).

The spelling of 21126288 in words is "twenty-one million, one hundred twenty-six thousand, two hundred eighty-eight".