21544072 has 32 divisors (see below), whose sum is σ = 44413920. Its totient is φ = 9715840.

The previous prime is 21544069. The next prime is 21544087. The reversal of 21544072 is 27044512.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11163 + ... + 12949.

It is an arithmetic number, because the mean of its divisors is an integer number (1387935).

Almost surely, 2^21544072 is an apocalyptic number.

21544072 is a gapful number since it is divisible by the number (22) 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 21544072, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22206960).

21544072 is an abundant number, since it is smaller than the sum of its proper divisors (22869848).

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

21544072 is a wasteful number, since it uses less digits than its factorization.

21544072 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1941 (or 1937 counting only the distinct ones).

The product of its (nonzero) digits is 2240, while the sum is 25.

The square root of 21544072 is about 4641.5592207792. The cubic root of 21544072 is about 278.2547567243.

Adding to 21544072 its reverse (27044512), we get a palindrome (48588584).

It can be divided in two parts, 215440 and 72, that added together give a palindrome (215512).

The spelling of 21544072 in words is "twenty-one million, five hundred forty-four thousand, seventy-two".