21234528 has 96 divisors (see below), whose sum is σ = 70801920. Its totient is φ = 6065280.

The previous prime is 21234523. The next prime is 21234529. The reversal of 21234528 is 82543212.

It is a tau number, because it is divible by the number of its divisors (96).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21234523) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4293 + ... + 7803.

It is an arithmetic number, because the mean of its divisors is an integer number (737520).

Almost surely, 2^21234528 is an apocalyptic number.

21234528 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21234528, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35400960).

21234528 is an abundant number, since it is smaller than the sum of its proper divisors (49567392).

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

21234528 is a wasteful number, since it uses less digits than its factorization.

21234528 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3537 (or 3523 counting only the distinct ones).

The product of its digits is 3840, while the sum is 27.

The square root of 21234528 is about 4608.0937490463. The cubic root of 21234528 is about 276.9156733063.

The spelling of 21234528 in words is "twenty-one million, two hundred thirty-four thousand, five hundred twenty-eight".