21528227 has 8 divisors (see below), whose sum is σ = 24677376. Its totient is φ = 18397512.

The previous prime is 21528223. The next prime is 21528257. The reversal of 21528227 is 72282512.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21528227 - 2² = 21528223 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21528227.

It is not an unprimeable number, because it can be changed into a prime (21528223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2003 + ... + 6860.

It is an arithmetic number, because the mean of its divisors is an integer number (3084672).

Almost surely, 2^21528227 is an apocalyptic number.

21528227 is a deficient number, since it is larger than the sum of its proper divisors (3149149).

21528227 is an equidigital number, since it uses as much as digits as its factorization.

21528227 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9217.

The product of its digits is 4480, while the sum is 29.

The square root of 21528227 is about 4639.8520450549. The cubic root of 21528227 is about 278.1865240655.

The spelling of 21528227 in words is "twenty-one million, five hundred twenty-eight thousand, two hundred twenty-seven".