21730368 has 56 divisors (see below), whose sum is σ = 62727840. Its totient is φ = 6584320.

The previous prime is 21730363. The next prime is 21730391. The reversal of 21730368 is 86303712.

It is not an unprimeable number, because it can be changed into a prime (21730363) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3033 + ... + 7256.

It is an arithmetic number, because the mean of its divisors is an integer number (1120140).

Almost surely, 2^21730368 is an apocalyptic number.

It is an amenable number.

21730368 is an abundant number, since it is smaller than the sum of its proper divisors (40997472).

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

21730368 is a wasteful number, since it uses less digits than its factorization.

21730368 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10315 (or 10305 counting only the distinct ones).

The product of its (nonzero) digits is 6048, while the sum is 30.

The square root of 21730368 is about 4661.5842800490. The cubic root of 21730368 is about 279.0544979035.

It can be divided in two parts, 217 and 30368, that multiplied together give a palindrome (6589856).

The spelling of 21730368 in words is "twenty-one million, seven hundred thirty thousand, three hundred sixty-eight".