21544442 has 16 divisors (see below), whose sum is σ = 35116800. Its totient is φ = 9875520.

The previous prime is 21544427. The next prime is 21544451. The reversal of 21544442 is 24444512.

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, 7967 + ... + 10322.

It is an arithmetic number, because the mean of its divisors is an integer number (2194800).

Almost surely, 2^21544442 is an apocalyptic number.

21544442 is a deficient number, since it is larger than the sum of its proper divisors (13572358).

21544442 is a wasteful number, since it uses less digits than its factorization.

21544442 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18341.

The product of its digits is 5120, while the sum is 26.

The square root of 21544442 is about 4641.5990779041. The cubic root of 21544442 is about 278.2563496400.

Adding to 21544442 its reverse (24444512), we get a palindrome (45988954).

The spelling of 21544442 in words is "twenty-one million, five hundred forty-four thousand, four hundred forty-two".