21768544 has 36 divisors (see below), whose sum is σ = 49857444. Its totient is φ = 9328704.

The previous prime is 21768533. The next prime is 21768553. The reversal of 21768544 is 44586712.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 5374 + ... + 8509.

It is an arithmetic number, because the mean of its divisors is an integer number (1384929).

Almost surely, 2^21768544 is an apocalyptic number.

It is an amenable number.

21768544 is an abundant number, since it is smaller than the sum of its proper divisors (28088900).

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

21768544 is a wasteful number, since it uses less digits than its factorization.

21768544 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13907 (or 13892 counting only the distinct ones).

The product of its digits is 53760, while the sum is 37.

The square root of 21768544 is about 4665.6772284418. The cubic root of 21768544 is about 279.2178169980.

The spelling of 21768544 in words is "twenty-one million, seven hundred sixty-eight thousand, five hundred forty-four".