21224064 has 64 divisors (see below), whose sum is σ = 59364000. Its totient is φ = 6700032.

The previous prime is 21224053. The next prime is 21224081. The reversal of 21224064 is 46042212.

It is a tau number, because it is divible by the number of its divisors (64).

It is a self number, because there is not a number n which added to its sum of digits gives 21224064.

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, 5842 + ... + 8750.

Almost surely, 2^21224064 is an apocalyptic number.

21224064 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 21224064, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29682000).

21224064 is an abundant number, since it is smaller than the sum of its proper divisors (38139936).

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

21224064 is a wasteful number, since it uses less digits than its factorization.

21224064 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2945 (or 2933 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 21.

The square root of 21224064 is about 4606.9582155691. The cubic root of 21224064 is about 276.8701794499.

Adding to 21224064 its reverse (46042212), we get a palindrome (67266276).

The spelling of 21224064 in words is "twenty-one million, two hundred twenty-four thousand, sixty-four".