21730752 has 84 divisors (see below), whose sum is σ = 64349376. Its totient is φ = 7004160.

The previous prime is 21730747. The next prime is 21730759. The reversal of 21730752 is 25703712.

It is a zygodrome in base 3.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21730759) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 17248 + ... + 18464.

It is an arithmetic number, because the mean of its divisors is an integer number (766064).

Almost surely, 2^21730752 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21730752, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32174688).

21730752 is an abundant number, since it is smaller than the sum of its proper divisors (42618624).

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

21730752 is a wasteful number, since it uses less digits than its factorization.

21730752 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1266 (or 1253 counting only the distinct ones).

The product of its (nonzero) digits is 2940, while the sum is 27.

The square root of 21730752 is about 4661.6254675810. The cubic root of 21730752 is about 279.0561416293.

The spelling of 21730752 in words is "twenty-one million, seven hundred thirty thousand, seven hundred fifty-two".