27717721 has 4 divisors (see below), whose sum is σ = 27771444. Its totient is φ = 27664000.

The previous prime is 27717647. The next prime is 27717731. The reversal of 27717721 is 12771772.

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

It can be written as a sum of positive squares in 2 ways, for example, as 15015625 + 12702096 = 3875^2 + 3564^2 .

It is a cyclic number.

It is not a de Polignac number, because 27717721 - 2¹¹ = 27715673 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (27717731) 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 3 ways as a sum of consecutive naturals, for example, 26080 + ... + 27121.

It is an arithmetic number, because the mean of its divisors is an integer number (6942861).

Almost surely, 2^27717721 is an apocalyptic number.

It is an amenable number.

27717721 is a deficient number, since it is larger than the sum of its proper divisors (53723).

27717721 is an equidigital number, since it uses as much as digits as its factorization.

27717721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53722.

The product of its digits is 9604, while the sum is 34.

The square root of 27717721 is about 5264.7621978585. The cubic root of 27717721 is about 302.6350138377.

The spelling of 27717721 in words is "twenty-seven million, seven hundred seventeen thousand, seven hundred twenty-one".