21744769 has 4 divisors (see below), whose sum is σ = 21825280. Its totient is φ = 21664260.

The previous prime is 21744763. The next prime is 21744803. The reversal of 21744769 is 96744712.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21744769 - 2³ = 21744761 is a prime.

It is a super-2 number, since 2×21744769² = 945669957726722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21744761) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 39849 + ... + 40390.

It is an arithmetic number, because the mean of its divisors is an integer number (5456320).

Almost surely, 2^21744769 is an apocalyptic number.

It is an amenable number.

21744769 is a deficient number, since it is larger than the sum of its proper divisors (80511).

21744769 is an equidigital number, since it uses as much as digits as its factorization.

21744769 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80510.

The product of its digits is 84672, while the sum is 40.

The square root of 21744769 is about 4663.1286707531. The cubic root of 21744769 is about 279.1161286501.

The spelling of 21744769 in words is "twenty-one million, seven hundred forty-four thousand, seven hundred sixty-nine".