21482784 has 72 divisors (see below), whose sum is σ = 61801740. Its totient is φ = 7077888.

The previous prime is 21482779. The next prime is 21482789. The reversal of 21482784 is 48728412.

It is an interprime number because it is at equal distance from previous prime (21482779) and next prime (21482789).

It can be written as a sum of positive squares in 2 ways, for example, as 21344400 + 138384 = 4620^2 + 372^2 .

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 a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21482789) 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, 27552 + ... + 28320.

Almost surely, 2^21482784 is an apocalyptic number.

21482784 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21482784, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30900870).

21482784 is an abundant number, since it is smaller than the sum of its proper divisors (40318956).

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

21482784 is a wasteful number, since it uses less digits than its factorization.

21482784 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 882 (or 871 counting only the distinct ones).

The product of its digits is 28672, while the sum is 36.

The square root of 21482784 is about 4634.9524269403. The cubic root of 21482784 is about 277.9906488927.

The spelling of 21482784 in words is "twenty-one million, four hundred eighty-two thousand, seven hundred eighty-four".