21072168 has 96 divisors (see below), whose sum is σ = 62899200. Its totient is φ = 6332544.

The previous prime is 21072137. The next prime is 21072169. The reversal of 21072168 is 86127012.

It is not an unprimeable number, because it can be changed into a prime (21072169) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 43753 + ... + 44231.

It is an arithmetic number, because the mean of its divisors is an integer number (655200).

Almost surely, 2^21072168 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 21072168, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31449600).

21072168 is an abundant number, since it is smaller than the sum of its proper divisors (41827032).

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

21072168 is a wasteful number, since it uses less digits than its factorization.

21072168 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 551 (or 544 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 27.

The square root of 21072168 is about 4590.4431158658. The cubic root of 21072168 is about 276.2080976281.

The spelling of 21072168 in words is "twenty-one million, seventy-two thousand, one hundred sixty-eight".