21238544 has 10 divisors (see below), whose sum is σ = 41149710. Its totient is φ = 10619264.

The previous prime is 21238543. The next prime is 21238549. The reversal of 21238544 is 44583212.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 20976400 + 262144 = 4580^2 + 512^2 .

It is not an unprimeable number, because it can be changed into a prime (21238543) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 663689 + ... + 663720.

It is an arithmetic number, because the mean of its divisors is an integer number (4114971).

Almost surely, 2^21238544 is an apocalyptic number.

It is an amenable number.

21238544 is a deficient number, since it is larger than the sum of its proper divisors (19911166).

21238544 is a wasteful number, since it uses less digits than its factorization.

21238544 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1327417 (or 1327411 counting only the distinct ones).

The product of its digits is 7680, while the sum is 29.

The square root of 21238544 is about 4608.5294834687. The cubic root of 21238544 is about 276.9331295180.

The spelling of 21238544 in words is "twenty-one million, two hundred thirty-eight thousand, five hundred forty-four".