21544042 has 16 divisors (see below), whose sum is σ = 36003240. Its totient is φ = 9600192.

The previous prime is 21544037. The next prime is 21544057. The reversal of 21544042 is 24044512.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 7338681 + 14205361 = 2709^2 + 3769^2 .

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, 13533 + ... + 15040.

Almost surely, 2^21544042 is an apocalyptic number.

21544042 is a deficient number, since it is larger than the sum of its proper divisors (14459198).

21544042 is a wasteful number, since it uses less digits than its factorization.

21544042 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28617.

The product of its (nonzero) digits is 1280, while the sum is 22.

The square root of 21544042 is about 4641.5559891054. Note that the first 3 decimals coincide. The cubic root of 21544042 is about 278.2546275682.

Adding to 21544042 its reverse (24044512), we get a palindrome (45588554).

The spelling of 21544042 in words is "twenty-one million, five hundred forty-four thousand, forty-two".