21447444 has 24 divisors (see below), whose sum is σ = 50893920. Its totient is φ = 7027744.

The previous prime is 21447427. The next prime is 21447509. The reversal of 21447444 is 44474412.

It is a congruent number.

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, 14439 + ... + 15854.

It is an arithmetic number, because the mean of its divisors is an integer number (2120580).

Almost surely, 2^21447444 is an apocalyptic number.

It is an amenable number.

21447444 is an abundant number, since it is smaller than the sum of its proper divisors (29446476).

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

21447444 is a wasteful number, since it uses less digits than its factorization.

21447444 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30359 (or 30357 counting only the distinct ones).

The product of its digits is 14336, while the sum is 30.

The square root of 21447444 is about 4631.1385209255. The cubic root of 21447444 is about 277.8381301516.

The spelling of 21447444 in words is "twenty-one million, four hundred forty-seven thousand, four hundred forty-four".