3987905 has 4 divisors (see below), whose sum is σ = 4785492. Its totient is φ = 3190320.

The previous prime is 3987887. The next prime is 3987913. The reversal of 3987905 is 5097893.

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 543169 + 3444736 = 737^2 + 1856^2 .

It is not a de Polignac number, because 3987905 - 2⁸ = 3987649 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 398786 + ... + 398795.

It is an arithmetic number, because the mean of its divisors is an integer number (1196373).

Almost surely, 2^3987905 is an apocalyptic number.

It is an amenable number.

3987905 is a deficient number, since it is larger than the sum of its proper divisors (797587).

3987905 is an equidigital number, since it uses as much as digits as its factorization.

3987905 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 797586.

The product of its (nonzero) digits is 68040, while the sum is 41.

The square root of 3987905 is about 1996.9739607716. The cubic root of 3987905 is about 158.5799468642.

The spelling of 3987905 in words is "three million, nine hundred eighty-seven thousand, nine hundred five".