21383168 has 48 divisors (see below), whose sum is σ = 43783740. Its totient is φ = 10436608.

The previous prime is 21383143. The next prime is 21383177. The reversal of 21383168 is 86138312.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 17572864 + 3810304 = 4192^2 + 1952^2 .

It is a Harshad number since it is a multiple of its sum of digits (32).

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 108446 + ... + 108642.

Almost surely, 2^21383168 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 21383168, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21891870).

21383168 is an abundant number, since it is smaller than the sum of its proper divisors (22400572).

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

21383168 is an equidigital number, since it uses as much as digits as its factorization.

21383168 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 272 (or 252 counting only the distinct ones).

The product of its digits is 6912, while the sum is 32.

The square root of 21383168 is about 4624.1937675664. The cubic root of 21383168 is about 277.5603007231.

The spelling of 21383168 in words is "twenty-one million, three hundred eighty-three thousand, one hundred sixty-eight".