21057528 has 16 divisors (see below), whose sum is σ = 52643880. Its totient is φ = 7019168.

The previous prime is 21057523. The next prime is 21057541. The reversal of 21057528 is 82575012.

It is a junction number, because it is equal to n+sod(n) for n = 21057495 and 21057504.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21057521) 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 3 ways as a sum of consecutive naturals, for example, 438675 + ... + 438722.

Almost surely, 2^21057528 is an apocalyptic number.

It is an amenable number.

21057528 is an abundant number, since it is smaller than the sum of its proper divisors (31586352).

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

21057528 is a wasteful number, since it uses less digits than its factorization.

21057528 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 877406 (or 877402 counting only the distinct ones).

The product of its (nonzero) digits is 5600, while the sum is 30.

The square root of 21057528 is about 4588.8482215040. The cubic root of 21057528 is about 276.1441171307.

The spelling of 21057528 in words is "twenty-one million, fifty-seven thousand, five hundred twenty-eight".