21936672 has 72 divisors (see below), whose sum is σ = 63488880. Its totient is φ = 7182720.

The previous prime is 21936667. The next prime is 21936679. The reversal of 21936672 is 27663912.

It is a tau number, because it is divible by the number of its divisors (72).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (21936679) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 16347 + ... + 17637.

It is an arithmetic number, because the mean of its divisors is an integer number (881790).

Almost surely, 2^21936672 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 21936672, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31744440).

21936672 is an abundant number, since it is smaller than the sum of its proper divisors (41552208).

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

21936672 is a wasteful number, since it uses less digits than its factorization.

21936672 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1366 (or 1355 counting only the distinct ones).

The product of its digits is 27216, while the sum is 36.

The square root of 21936672 is about 4683.6601072238. The cubic root of 21936672 is about 279.9348147577.

The spelling of 21936672 in words is "twenty-one million, nine hundred thirty-six thousand, six hundred seventy-two".