3905 has 8 divisors (see below), whose sum is σ = 5184. Its totient is φ = 2800.

The previous prime is 3889. The next prime is 3907. The reversal of 3905 is 5093.

3905 = T₃₇ + T₃₈ + ... + T₄₁.

3905 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 3905 - 2⁴ = 3889 is a prime.

It is a Duffinian number.

It is a plaindrome in base 14 and base 15.

It is a nialpdrome in base 5 and base 16.

It is not an unprimeable number, because it can be changed into a prime (3907) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20 + ... + 90.

It is an arithmetic number, because the mean of its divisors is an integer number (648).

It is a Proth number, since it is equal to 61 ⋅ 2⁶ + 1 and 61 < 2⁶.

2³⁹⁰⁵ is an apocalyptic number.

It is an amenable number.

3905 is a deficient number, since it is larger than the sum of its proper divisors (1279).

3905 is a wasteful number, since it uses less digits than its factorization.

3905 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 87.

The product of its (nonzero) digits is 135, while the sum is 17.

The square root of 3905 is about 62.4899991999. The cubic root of 3905 is about 15.7473330497.

Adding to 3905 its reverse (5093), we get a palindrome (8998).

The spelling of 3905 in words is "three thousand, nine hundred five".