21549312 has 108 divisors (see below), whose sum is σ = 63772800. Its totient is φ = 6994944.

The previous prime is 21549301. The next prime is 21549389. The reversal of 21549312 is 21394512.

It is a zygodrome in base 3.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 108189 + ... + 108387.

Almost surely, 2^21549312 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 21549312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31886400).

21549312 is an abundant number, since it is smaller than the sum of its proper divisors (42223488).

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

21549312 is a wasteful number, since it uses less digits than its factorization.

21549312 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 268 (or 251 counting only the distinct ones).

The product of its digits is 2160, while the sum is 27.

The square root of 21549312 is about 4642.1236519507. The cubic root of 21549312 is about 278.2773141550.

The spelling of 21549312 in words is "twenty-one million, five hundred forty-nine thousand, three hundred twelve".