21789744 has 40 divisors (see below), whose sum is σ = 57816240. Its totient is φ = 7066368.

The previous prime is 21789739. The next prime is 21789769. The reversal of 21789744 is 44798712.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 21789696 and 21789705.

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, 4359 + ... + 7910.

It is an arithmetic number, because the mean of its divisors is an integer number (1445406).

Almost surely, 2^21789744 is an apocalyptic number.

21789744 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21789744 is an abundant number, since it is smaller than the sum of its proper divisors (36026496).

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

21789744 is a wasteful number, since it uses less digits than its factorization.

21789744 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12317 (or 12311 counting only the distinct ones).

The product of its digits is 112896, while the sum is 42.

The square root of 21789744 is about 4667.9485858351. The cubic root of 21789744 is about 279.3084293537.

The spelling of 21789744 in words is "twenty-one million, seven hundred eighty-nine thousand, seven hundred forty-four".