21725056 has 32 divisors (see below), whose sum is σ = 45563400. Its totient is φ = 10289664.

The previous prime is 21725047. The next prime is 21725059. The reversal of 21725056 is 65052712.

It is a tau number, because it is divible by the number of its divisors (32).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21725059) 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, 2035 + ... + 6898.

Almost surely, 2^21725056 is an apocalyptic number.

It is an amenable number.

21725056 is an abundant number, since it is smaller than the sum of its proper divisors (23838344).

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

21725056 is an equidigital number, since it uses as much as digits as its factorization.

21725056 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8966 (or 8954 counting only the distinct ones).

The product of its (nonzero) digits is 4200, while the sum is 28.

The square root of 21725056 is about 4661.0144818483. The cubic root of 21725056 is about 279.0317577104.

Adding to 21725056 its reverse (65052712), we get a palindrome (86777768).

The spelling of 21725056 in words is "twenty-one million, seven hundred twenty-five thousand, fifty-six".