21716727 has 4 divisors (see below), whose sum is σ = 28955640. Its totient is φ = 14477816.

The previous prime is 21716713. The next prime is 21716729. The reversal of 21716727 is 72761712.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21716727 - 2¹² = 21712631 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21716729) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3619452 + ... + 3619457.

It is an arithmetic number, because the mean of its divisors is an integer number (7238910).

Almost surely, 2^21716727 is an apocalyptic number.

21716727 is a deficient number, since it is larger than the sum of its proper divisors (7238913).

21716727 is an equidigital number, since it uses as much as digits as its factorization.

21716727 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7238912.

The product of its digits is 8232, while the sum is 33.

The square root of 21716727 is about 4660.1209211779. The cubic root of 21716727 is about 278.9960945484.

The spelling of 21716727 in words is "twenty-one million, seven hundred sixteen thousand, seven hundred twenty-seven".