21164528 has 80 divisors (see below), whose sum is σ = 52496640. Its totient is φ = 8025600.

The previous prime is 21164509. The next prime is 21164567. The reversal of 21164528 is 82546112.

Its product of digits (3840) is a multiple of the sum of its prime divisors (480).

It is a self number, because there is not a number n which added to its sum of digits gives 21164528.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 50303 + ... + 50721.

It is an arithmetic number, because the mean of its divisors is an integer number (656208).

Almost surely, 2^21164528 is an apocalyptic number.

21164528 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 21164528, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26248320).

21164528 is an abundant number, since it is smaller than the sum of its proper divisors (31332112).

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

21164528 is a wasteful number, since it uses less digits than its factorization.

21164528 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 486 (or 480 counting only the distinct ones).

The product of its digits is 3840, while the sum is 29.

The square root of 21164528 is about 4600.4921475860. The cubic root of 21164528 is about 276.6110525140.

The spelling of 21164528 in words is "twenty-one million, one hundred sixty-four thousand, five hundred twenty-eight".