21443430 has 16 divisors (see below), whose sum is σ = 51464304. Its totient is φ = 5718240.

The previous prime is 21443363. The next prime is 21443431. The reversal of 21443430 is 3434412.

It is a junction number, because it is equal to n+sod(n) for n = 21443397 and 21443406.

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 pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 357361 + ... + 357420.

It is an arithmetic number, because the mean of its divisors is an integer number (3216519).

Almost surely, 2^21443430 is an apocalyptic number.

21443430 is an abundant number, since it is smaller than the sum of its proper divisors (30020874).

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

21443430 is a wasteful number, since it uses less digits than its factorization.

21443430 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 714791.

The product of its (nonzero) digits is 1152, while the sum is 21.

The square root of 21443430 is about 4630.7051298911. The cubic root of 21443430 is about 277.8207961228.

Adding to 21443430 its reverse (3434412), we get a palindrome (24877842).

The spelling of 21443430 in words is "twenty-one million, four hundred forty-three thousand, four hundred thirty".