21528573 has 8 divisors (see below), whose sum is σ = 31314336. Its totient is φ = 13047600.

The previous prime is 21528553. The next prime is 21528581. The reversal of 21528573 is 37582512.

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

It is not a de Polignac number, because 21528573 - 2¹⁰ = 21527549 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33), and also a Moran number because the ratio is a prime number: 652381 = 21528573 / (2 + 1 + 5 + 2 + 8 + 5 + 7 + 3).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21528553) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 326158 + ... + 326223.

It is an arithmetic number, because the mean of its divisors is an integer number (3914292).

Almost surely, 2^21528573 is an apocalyptic number.

It is an amenable number.

21528573 is a deficient number, since it is larger than the sum of its proper divisors (9785763).

21528573 is a wasteful number, since it uses less digits than its factorization.

21528573 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 652395.

The product of its digits is 16800, while the sum is 33.

The square root of 21528573 is about 4639.8893305768. The cubic root of 21528573 is about 278.1880143883.

The spelling of 21528573 in words is "twenty-one million, five hundred twenty-eight thousand, five hundred seventy-three".