21270528 has 78 divisors (see below), whose sum is σ = 61547174. Its totient is φ = 7077888.

The previous prime is 21270527. The next prime is 21270533. The reversal of 21270528 is 82507212.

It can be written as a sum of positive squares in only one way, i.e., 21233664 + 36864 = 4608^2 + 192^2 .

It is a super-2 number, since 2×21270528² = 904870722797568, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21270527) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 36576 + ... + 37152.

Almost surely, 2^21270528 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 21270528, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30773587).

21270528 is an abundant number, since it is smaller than the sum of its proper divisors (40276646).

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

21270528 is an equidigital number, since it uses as much as digits as its factorization.

21270528 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 607 (or 582 counting only the distinct ones).

The product of its (nonzero) digits is 2240, while the sum is 27.

The square root of 21270528 is about 4611.9982653943. The cubic root of 21270528 is about 277.0720748034.

The spelling of 21270528 in words is "twenty-one million, two hundred seventy thousand, five hundred twenty-eight".