21445328 has 10 divisors (see below), whose sum is σ = 41550354. Its totient is φ = 10722656.

The previous prime is 21445327. The next prime is 21445331. The reversal of 21445328 is 82354412.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 20539024 + 906304 = 4532^2 + 952^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21445328.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21445327) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 670151 + ... + 670182.

Almost surely, 2^21445328 is an apocalyptic number.

It is an amenable number.

21445328 is a deficient number, since it is larger than the sum of its proper divisors (20105026).

21445328 is a wasteful number, since it uses less digits than its factorization.

21445328 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1340341 (or 1340335 counting only the distinct ones).

The product of its digits is 7680, while the sum is 29.

The square root of 21445328 is about 4630.9100617481. The cubic root of 21445328 is about 277.8289927019.

The spelling of 21445328 in words is "twenty-one million, four hundred forty-five thousand, three hundred twenty-eight".