21018168 has 48 divisors (see below), whose sum is σ = 57787080. Its totient is φ = 6899904.

The previous prime is 21018167. The next prime is 21018191. The reversal of 21018168 is 86181012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21018163) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2646 + ... + 7002.

Almost surely, 2^21018168 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 21018168, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28893540).

21018168 is an abundant number, since it is smaller than the sum of its proper divisors (36768912).

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

21018168 is a wasteful number, since it uses less digits than its factorization.

21018168 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4436 (or 4429 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 27.

The square root of 21018168 is about 4584.5575577148. The cubic root of 21018168 is about 275.9719568231.

The spelling of 21018168 in words is "twenty-one million, eighteen thousand, one hundred sixty-eight".