3978391 has 16 divisors (see below), whose sum is σ = 4514400. Its totient is φ = 3483648.

The previous prime is 3978349. The next prime is 3978421. The reversal of 3978391 is 1938793.

It is a cyclic number.

It is not a de Polignac number, because 3978391 - 2⁷ = 3978263 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3978301) 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 15 ways as a sum of consecutive naturals, for example, 35151 + ... + 35263.

It is an arithmetic number, because the mean of its divisors is an integer number (282150).

Almost surely, 2^3978391 is an apocalyptic number.

3978391 is a deficient number, since it is larger than the sum of its proper divisors (536009).

3978391 is a wasteful number, since it uses less digits than its factorization.

3978391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 258.

The product of its digits is 40824, while the sum is 40.

The square root of 3978391 is about 1994.5904341493. The cubic root of 3978391 is about 158.4537376553.

The spelling of 3978391 in words is "three million, nine hundred seventy-eight thousand, three hundred ninety-one".