21716544 has 56 divisors (see below), whose sum is σ = 60492640. Its totient is φ = 6856704.

The previous prime is 21716533. The next prime is 21716567. The reversal of 21716544 is 44561712.

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 7 ways as a sum of consecutive naturals, for example, 672 + ... + 6624.

Almost surely, 2^21716544 is an apocalyptic number.

21716544 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 21716544, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30246320).

21716544 is an abundant number, since it is smaller than the sum of its proper divisors (38776096).

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

21716544 is a wasteful number, since it uses less digits than its factorization.

21716544 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5987 (or 5977 counting only the distinct ones).

The product of its digits is 6720, while the sum is 30.

The square root of 21716544 is about 4660.1012864529. The cubic root of 21716544 is about 278.9953108756.

It can be divided in two parts, 217 and 16544, that added together give a palindrome (16761).

The spelling of 21716544 in words is "twenty-one million, seven hundred sixteen thousand, five hundred forty-four".