21090528 has 72 divisors (see below), whose sum is σ = 60927048. Its totient is φ = 6918912.

The previous prime is 21090497. The next prime is 21090529. The reversal of 21090528 is 82509012.

It is a tau number, because it is divible by the number of its divisors (72).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21090529) 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, 18750 + ... + 19842.

It is an arithmetic number, because the mean of its divisors is an integer number (846209).

Almost surely, 2^21090528 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 21090528, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30463524).

21090528 is an abundant number, since it is smaller than the sum of its proper divisors (39836520).

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

21090528 is a wasteful number, since it uses less digits than its factorization.

21090528 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1176 (or 1165 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 27.

The square root of 21090528 is about 4592.4424873916. The cubic root of 21090528 is about 276.2882935934.

The spelling of 21090528 in words is "twenty-one million, ninety thousand, five hundred twenty-eight".