21006528 has 56 divisors (see below), whose sum is σ = 57101232. Its totient is φ = 6810624.

The previous prime is 21006523. The next prime is 21006547. The reversal of 21006528 is 82560012.

It is a super-2 number, since 2×21006528² = 882548437229568, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a junction number, because it is equal to n+sod(n) for n = 21006498 and 21006507.

It is not an unprimeable number, because it can be changed into a prime (21006523) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5626 + ... + 8582.

Almost surely, 2^21006528 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 21006528, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28550616).

21006528 is an abundant number, since it is smaller than the sum of its proper divisors (36094704).

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

21006528 is a wasteful number, since it uses less digits than its factorization.

21006528 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3009 (or 2999 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 24.

The square root of 21006528 is about 4583.2879028051. The cubic root of 21006528 is about 275.9210023860.

The spelling of 21006528 in words is "twenty-one million, six thousand, five hundred twenty-eight".