21124438 has 16 divisors (see below), whose sum is σ = 34333200. Its totient is φ = 9709056.

The previous prime is 21124391. The next prime is 21124459. The reversal of 21124438 is 83442112.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 5763 + ... + 8686.

It is an arithmetic number, because the mean of its divisors is an integer number (2145825).

Almost surely, 2^21124438 is an apocalyptic number.

21124438 is a deficient number, since it is larger than the sum of its proper divisors (13208762).

21124438 is a wasteful number, since it uses less digits than its factorization.

21124438 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14511.

The product of its digits is 1536, while the sum is 25.

The square root of 21124438 is about 4596.1329397658. The cubic root of 21124438 is about 276.4362892449.

It can be divided in two parts, 211 and 24438, that added together give a square (24649 = 157²).

The spelling of 21124438 in words is "twenty-one million, one hundred twenty-four thousand, four hundred thirty-eight".