27724561 has 4 divisors (see below), whose sum is σ = 28179124. Its totient is φ = 27270000.

The previous prime is 27724559. The next prime is 27724583. The reversal of 27724561 is 16542772.

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 15752961 + 11971600 = 3969^2 + 3460^2 .

It is a cyclic number.

It is not a de Polignac number, because 27724561 - 2¹ = 27724559 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (27724531) 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, 227190 + ... + 227311.

It is an arithmetic number, because the mean of its divisors is an integer number (7044781).

Almost surely, 2^27724561 is an apocalyptic number.

It is an amenable number.

27724561 is a deficient number, since it is larger than the sum of its proper divisors (454563).

27724561 is an equidigital number, since it uses as much as digits as its factorization.

27724561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 454562.

The product of its digits is 23520, while the sum is 34.

The square root of 27724561 is about 5265.4117597772. The cubic root of 27724561 is about 302.6599058943.

The spelling of 27724561 in words is "twenty-seven million, seven hundred twenty-four thousand, five hundred sixty-one".