21125444 has 6 divisors (see below), whose sum is σ = 36969534. Its totient is φ = 10562720.

The previous prime is 21125443. The next prime is 21125471. The reversal of 21125444 is 44452112.

It can be written as a sum of positive squares in only one way, i.e., 20811844 + 313600 = 4562^2 + 560^2 .

It is not an unprimeable number, because it can be changed into a prime (21125443) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2640677 + ... + 2640684.

It is an arithmetic number, because the mean of its divisors is an integer number (6161589).

Almost surely, 2^21125444 is an apocalyptic number.

It is an amenable number.

21125444 is a deficient number, since it is larger than the sum of its proper divisors (15844090).

21125444 is a wasteful number, since it uses less digits than its factorization.

21125444 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5281365 (or 5281363 counting only the distinct ones).

The product of its digits is 1280, while the sum is 23.

The square root of 21125444 is about 4596.2423782912. The cubic root of 21125444 is about 276.4406773773.

Adding to 21125444 its reverse (44452112), we get a palindrome (65577556).

The spelling of 21125444 in words is "twenty-one million, one hundred twenty-five thousand, four hundred forty-four".