21744713 has 4 divisors (see below), whose sum is σ = 22250448. Its totient is φ = 21238980.

The previous prime is 21744631. The next prime is 21744727. The reversal of 21744713 is 31744712.

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 a de Polignac number, because none of the positive numbers 2^k-21744713 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21744763) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 252803 + ... + 252888.

It is an arithmetic number, because the mean of its divisors is an integer number (5562612).

Almost surely, 2^21744713 is an apocalyptic number.

It is an amenable number.

21744713 is a deficient number, since it is larger than the sum of its proper divisors (505735).

21744713 is an equidigital number, since it uses as much as digits as its factorization.

21744713 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 505734.

The product of its digits is 4704, while the sum is 29.

The square root of 21744713 is about 4663.1226661970. The cubic root of 21744713 is about 279.1158890444.

Subtracting 21744713 from its reverse (31744712), we obtain a palindrome (9999999).

The spelling of 21744713 in words is "twenty-one million, seven hundred forty-four thousand, seven hundred thirteen".