21616128 has 60 divisors (see below), whose sum is σ = 62398908. Its totient is φ = 7203840.

The previous prime is 21616123. The next prime is 21616139. The reversal of 21616128 is 82161612.

21616128 is a `hidden beast` number, since 21 + 616 + 1 + 28 = 666.

It is a nude number because it is divisible by every one of its digits and also a Zuckerman number because it is divisible by the product of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21616123) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2263 + ... + 6953.

Almost surely, 2^21616128 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21616128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31199454).

21616128 is an abundant number, since it is smaller than the sum of its proper divisors (40782780).

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

21616128 is an equidigital number, since it uses as much as digits as its factorization.

21616128 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4715 (or 4696 counting only the distinct ones).

The product of its digits is 1152, while the sum is 27.

The square root of 21616128 is about 4649.3147882242. The cubic root of 21616128 is about 278.5646271656.

The spelling of 21616128 in words is "twenty-one million, six hundred sixteen thousand, one hundred twenty-eight".