21489216 has 112 divisors (see below), whose sum is σ = 66324480. Its totient is φ = 6013440.

The previous prime is 21489191. The next prime is 21489233. The reversal of 21489216 is 61298412.

It is a tau number, because it is divible by the number of its divisors (112).

It is a congruent number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 79161 + ... + 79431.

Almost surely, 2^21489216 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 21489216, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33162240).

21489216 is an abundant number, since it is smaller than the sum of its proper divisors (44835264).

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

21489216 is a wasteful number, since it uses less digits than its factorization.

21489216 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 352 (or 342 counting only the distinct ones).

The product of its digits is 6912, while the sum is 33.

The square root of 21489216 is about 4635.6462332667. The cubic root of 21489216 is about 278.0183898260.

The spelling of 21489216 in words is "twenty-one million, four hundred eighty-nine thousand, two hundred sixteen".