21443284 has 6 divisors (see below), whose sum is σ = 37525754. Its totient is φ = 10721640.

The previous prime is 21443281. The next prime is 21443311. The reversal of 21443284 is 48234412.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 11696400 + 9746884 = 3420^2 + 3122^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21443281) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2680407 + ... + 2680414.

Almost surely, 2^21443284 is an apocalyptic number.

It is an amenable number.

21443284 is a deficient number, since it is larger than the sum of its proper divisors (16082470).

21443284 is a wasteful number, since it uses less digits than its factorization.

21443284 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5360825 (or 5360823 counting only the distinct ones).

The product of its digits is 6144, while the sum is 28.

The square root of 21443284 is about 4630.6893655265. The cubic root of 21443284 is about 277.8201655966.

Adding to 21443284 its reverse (48234412), we get a palindrome (69677696).

The spelling of 21443284 in words is "twenty-one million, four hundred forty-three thousand, two hundred eighty-four".