21071128 has 48 divisors (see below), whose sum is σ = 44593920. Its totient is φ = 9278016.

The previous prime is 21071123. The next prime is 21071137. The reversal of 21071128 is 82117012.

It is a junction number, because it is equal to n+sod(n) for n = 21071099 and 21071108.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21071123) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 54825 + ... + 55207.

It is an arithmetic number, because the mean of its divisors is an integer number (929040).

Almost surely, 2^21071128 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 21071128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22296960).

21071128 is an abundant number, since it is smaller than the sum of its proper divisors (23522792).

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

21071128 is a wasteful number, since it uses less digits than its factorization.

21071128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 448 (or 421 counting only the distinct ones).

The product of its (nonzero) digits is 224, while the sum is 22.

The square root of 21071128 is about 4590.3298356436. The cubic root of 21071128 is about 276.2035535434.

The spelling of 21071128 in words is "twenty-one million, seventy-one thousand, one hundred twenty-eight".