21318168 has 16 divisors (see below), whose sum is σ = 53295480. Its totient is φ = 7106048.

The previous prime is 21318149. The next prime is 21318181. The reversal of 21318168 is 86181312.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

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, 444105 + ... + 444152.

Almost surely, 2^21318168 is an apocalyptic number.

It is an amenable number.

21318168 is an abundant number, since it is smaller than the sum of its proper divisors (31977312).

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

21318168 is a wasteful number, since it uses less digits than its factorization.

21318168 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 888266 (or 888262 counting only the distinct ones).

The product of its digits is 2304, while the sum is 30.

The square root of 21318168 is about 4617.1601661627. The cubic root of 21318168 is about 277.2787750686.

It can be divided in two parts, 213 and 18168, that added together give a palindrome (18381).

The spelling of 21318168 in words is "twenty-one million, three hundred eighteen thousand, one hundred sixty-eight".