3978805 has 4 divisors (see below), whose sum is σ = 4774572. Its totient is φ = 3183040.

The previous prime is 3978803. The next prime is 3978811. The reversal of 3978805 is 5088793.

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 2630884 + 1347921 = 1622^2 + 1161^2 .

It is not a de Polignac number, because 3978805 - 2¹ = 3978803 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3978803) 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, 397876 + ... + 397885.

It is an arithmetic number, because the mean of its divisors is an integer number (1193643).

Almost surely, 2^3978805 is an apocalyptic number.

It is an amenable number.

3978805 is a deficient number, since it is larger than the sum of its proper divisors (795767).

3978805 is an equidigital number, since it uses as much as digits as its factorization.

3978805 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 795766.

The product of its (nonzero) digits is 60480, while the sum is 40.

The square root of 3978805 is about 1994.6942121538. The cubic root of 3978805 is about 158.4592338112.

The spelling of 3978805 in words is "three million, nine hundred seventy-eight thousand, eight hundred five".