3978405 has 24 divisors (see below), whose sum is σ = 6945120. Its totient is φ = 2106720.

The previous prime is 3978349. The next prime is 3978421. The reversal of 3978405 is 5048793.

It is not a de Polignac number, because 3978405 - 2⁹ = 3977893 is a prime.

It is a nialpdrome in base 9.

It is a self number, because there is not a number n which added to its sum of digits gives 3978405.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 9286 + ... + 9704.

It is an arithmetic number, because the mean of its divisors is an integer number (289380).

Almost surely, 2^3978405 is an apocalyptic number.

It is an amenable number.

3978405 is a deficient number, since it is larger than the sum of its proper divisors (2966715).

3978405 is a wasteful number, since it uses less digits than its factorization.

3978405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 641 (or 638 counting only the distinct ones).

The product of its (nonzero) digits is 30240, while the sum is 36.

The square root of 3978405 is about 1994.5939436387. The cubic root of 3978405 is about 158.4539235219.

The spelling of 3978405 in words is "three million, nine hundred seventy-eight thousand, four hundred five".