21443438 has 8 divisors (see below), whose sum is σ = 33858120. Its totient is φ = 10157400.

The previous prime is 21443437. The next prime is 21443447. The reversal of 21443438 is 83434412.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a self number, because there is not a number n which added to its sum of digits gives 21443438.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21443431) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 282113 + ... + 282188.

It is an arithmetic number, because the mean of its divisors is an integer number (4232265).

Almost surely, 2^21443438 is an apocalyptic number.

21443438 is a deficient number, since it is larger than the sum of its proper divisors (12414682).

21443438 is a wasteful number, since it uses less digits than its factorization.

21443438 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 564322.

The product of its digits is 9216, while the sum is 29.

The square root of 21443438 is about 4630.7059936904. The cubic root of 21443438 is about 277.8208306721.

The spelling of 21443438 in words is "twenty-one million, four hundred forty-three thousand, four hundred thirty-eight".