21768360 has 64 divisors (see below), whose sum is σ = 65638080. Its totient is φ = 5775360.

The previous prime is 21768349. The next prime is 21768361. The reversal of 21768360 is 6386712.

It is a super-2 number, since 2×21768360² = 947722994179200, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21768361) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 33640 + ... + 34280.

It is an arithmetic number, because the mean of its divisors is an integer number (1025595).

Almost surely, 2^21768360 is an apocalyptic number.

21768360 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21768360, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32819040).

21768360 is an abundant number, since it is smaller than the sum of its proper divisors (43869720).

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

21768360 is a wasteful number, since it uses less digits than its factorization.

21768360 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 938 (or 934 counting only the distinct ones).

The product of its (nonzero) digits is 12096, while the sum is 33.

The square root of 21768360 is about 4665.6575099336. The cubic root of 21768360 is about 279.2170302937.

The spelling of 21768360 in words is "twenty-one million, seven hundred sixty-eight thousand, three hundred sixty".