21442444 has 12 divisors (see below), whose sum is σ = 37611000. Its totient is φ = 10696448.

The previous prime is 21442439. The next prime is 21442451. The reversal of 21442444 is 44424412.

It is a nude number because it is divisible by every one of its digits.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 4174 + ... + 7765.

It is an arithmetic number, because the mean of its divisors is an integer number (3134250).

Almost surely, 2^21442444 is an apocalyptic number.

It is an amenable number.

21442444 is a deficient number, since it is larger than the sum of its proper divisors (16168556).

21442444 is a wasteful number, since it uses less digits than its factorization.

21442444 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12392 (or 12390 counting only the distinct ones).

The product of its digits is 4096, while the sum is 25.

The square root of 21442444 is about 4630.5986653995. The cubic root of 21442444 is about 277.8165378565.

Adding to 21442444 its reverse (44424412), we get a palindrome (65866856).

The spelling of 21442444 in words is "twenty-one million, four hundred forty-two thousand, four hundred forty-four".