21126744 has 40 divisors (see below), whose sum is σ = 59176260. Its totient is φ = 7042032.

The previous prime is 21126739. The next prime is 21126757. The reversal of 21126744 is 44762112.

It is a Harshad number since it is a multiple of its sum of digits (27).

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 9 ways as a sum of consecutive naturals, for example, 15654 + ... + 16949.

Almost surely, 2^21126744 is an apocalyptic number.

21126744 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21126744 is an abundant number, since it is smaller than the sum of its proper divisors (38049516).

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

21126744 is a wasteful number, since it uses less digits than its factorization.

21126744 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32621 (or 32608 counting only the distinct ones).

The product of its digits is 2688, while the sum is 27.

The square root of 21126744 is about 4596.3837959857. The cubic root of 21126744 is about 276.4463477198.

Adding to 21126744 its reverse (44762112), we get a palindrome (65888856).

The spelling of 21126744 in words is "twenty-one million, one hundred twenty-six thousand, seven hundred forty-four".