21144548 has 18 divisors (see below), whose sum is σ = 37822806. Its totient is φ = 10343008.

The previous prime is 21144547. The next prime is 21144551. The reversal of 21144548 is 84544112.

It can be written as a sum of positive squares in only one way, i.e., 12096484 + 9048064 = 3478^2 + 3008^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21144548.

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

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 7640 + ... + 10032.

It is an arithmetic number, because the mean of its divisors is an integer number (2101267).

Almost surely, 2^21144548 is an apocalyptic number.

It is an amenable number.

21144548 is a deficient number, since it is larger than the sum of its proper divisors (16678258).

21144548 is a wasteful number, since it uses less digits than its factorization.

21144548 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2491 (or 2442 counting only the distinct ones).

The product of its digits is 5120, while the sum is 29.

The square root of 21144548 is about 4598.3201280468. The cubic root of 21144548 is about 276.5239818445.

The spelling of 21144548 in words is "twenty-one million, one hundred forty-four thousand, five hundred forty-eight".