21144544 has 24 divisors (see below), whose sum is σ = 43439760. Its totient is φ = 10112256.

The previous prime is 21144469. The next prime is 21144547. The reversal of 21144544 is 44544112.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21144547) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13629 + ... + 15100.

It is an arithmetic number, because the mean of its divisors is an integer number (1809990).

Almost surely, 2^21144544 is an apocalyptic number.

It is an amenable number.

21144544 is an abundant number, since it is smaller than the sum of its proper divisors (22295216).

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

21144544 is a wasteful number, since it uses less digits than its factorization.

21144544 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28762 (or 28754 counting only the distinct ones).

The product of its digits is 2560, while the sum is 25.

The square root of 21144544 is about 4598.3196931053. The cubic root of 21144544 is about 276.5239644075.

Adding to 21144544 its reverse (44544112), we get a palindrome (65688656).

The spelling of 21144544 in words is "twenty-one million, one hundred forty-four thousand, five hundred forty-four".