21744468 has 18 divisors (see below), whose sum is σ = 54965274. Its totient is φ = 7248144.

The previous prime is 21744467. The next prime is 21744491. The reversal of 21744468 is 86444712.

It can be written as a sum of positive squares in only one way, i.e., 11168964 + 10575504 = 3342^2 + 3252^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a Harshad number since it is a multiple of its sum of digits (36), and also a Moran number because the ratio is a prime number: 604013 = 21744468 / (2 + 1 + 7 + 4 + 4 + 4 + 6 + 8).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21744467) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 301971 + ... + 302042.

Almost surely, 2^21744468 is an apocalyptic number.

It is an amenable number.

21744468 is an abundant number, since it is smaller than the sum of its proper divisors (33220806).

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

21744468 is a wasteful number, since it uses less digits than its factorization.

21744468 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 604023 (or 604018 counting only the distinct ones).

The product of its digits is 43008, while the sum is 36.

The square root of 21744468 is about 4663.0963961728. The cubic root of 21744468 is about 279.1148407643.

The spelling of 21744468 in words is "twenty-one million, seven hundred forty-four thousand, four hundred sixty-eight".