21284445 has 64 divisors (see below), whose sum is σ = 43352064. Its totient is φ = 8674560.

The previous prime is 21284423. The next prime is 21284489. The reversal of 21284445 is 54448212.

It is not a de Polignac number, because 21284445 - 2⁶ = 21284381 is a prime.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 42064 + ... + 42566.

It is an arithmetic number, because the mean of its divisors is an integer number (677376).

Almost surely, 2^21284445 is an apocalyptic number.

It is an amenable number.

21284445 is an abundant number, since it is smaller than the sum of its proper divisors (22067619).

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

21284445 is a wasteful number, since it uses less digits than its factorization.

21284445 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 562.

The product of its digits is 10240, while the sum is 30.

The square root of 21284445 is about 4613.5068006886. The cubic root of 21284445 is about 277.1324897179.

The spelling of 21284445 in words is "twenty-one million, two hundred eighty-four thousand, four hundred forty-five".