21534528 has 56 divisors (see below), whose sum is σ = 57972960. Its totient is φ = 7052800.

The previous prime is 21534517. The next prime is 21534533. The reversal of 21534528 is 82543512.

It is a hoax number, since the sum of its digits (30) coincides with the sum of the digits of its distinct prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 21534495 and 21534504.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10378 + ... + 12278.

Almost surely, 2^21534528 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 21534528, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28986480).

21534528 is an abundant number, since it is smaller than the sum of its proper divisors (36438432).

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

21534528 is a wasteful number, since it uses less digits than its factorization.

21534528 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1975 (or 1965 counting only the distinct ones).

The product of its digits is 9600, while the sum is 30.

The square root of 21534528 is about 4640.5310040986. The cubic root of 21534528 is about 278.2136618058.

It can be divided in two parts, 215 and 34528, that added together give a palindrome (34743).

The spelling of 21534528 in words is "twenty-one million, five hundred thirty-four thousand, five hundred twenty-eight".