27905 has 4 divisors (see below), whose sum is σ = 33492. Its totient is φ = 22320.

The previous prime is 27901. The next prime is 27917. The reversal of 27905 is 50972.

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 9409 + 18496 = 97^2 + 136^2 .

It is not a de Polignac number, because 27905 - 2² = 27901 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (27901) 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, 2786 + ... + 2795.

It is an arithmetic number, because the mean of its divisors is an integer number (8373).

It is a Proth number, since it is equal to 109 ⋅ 2⁸ + 1 and 109 < 2⁸.

2²⁷⁹⁰⁵ is an apocalyptic number.

It is an amenable number.

27905 is a deficient number, since it is larger than the sum of its proper divisors (5587).

27905 is an equidigital number, since it uses as much as digits as its factorization.

27905 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5586.

The product of its (nonzero) digits is 630, while the sum is 23.

The square root of 27905 is about 167.0478973229. The cubic root of 27905 is about 30.3315084305.

The spelling of 27905 in words is "twenty-seven thousand, nine hundred five".