21840528 has 20 divisors (see below), whose sum is σ = 56421488. Its totient is φ = 7280160.

The previous prime is 21840521. The next prime is 21840541. The reversal of 21840528 is 82504812.

It is a junction number, because it is equal to n+sod(n) for n = 21840495 and 21840504.

It is not an unprimeable number, because it can be changed into a prime (21840521) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 227458 + ... + 227553.

Almost surely, 2^21840528 is an apocalyptic number.

It is an amenable number.

21840528 is an abundant number, since it is smaller than the sum of its proper divisors (34580960).

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

21840528 is a wasteful number, since it uses less digits than its factorization.

21840528 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 455022 (or 455016 counting only the distinct ones).

The product of its (nonzero) digits is 5120, while the sum is 30.

The square root of 21840528 is about 4673.3850686628. The cubic root of 21840528 is about 279.5252499209.

The spelling of 21840528 in words is "twenty-one million, eight hundred forty thousand, five hundred twenty-eight".