3978215 has 4 divisors (see below), whose sum is σ = 4773864. Its totient is φ = 3182568.

The previous prime is 3978197. The next prime is 3978217. The reversal of 3978215 is 5128793.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5128793 = 23 ⋅222991.

It is a cyclic number.

It is not a de Polignac number, because 3978215 - 2¹⁶ = 3912679 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a zygodrome in base 6.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3978217) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 397817 + ... + 397826.

It is an arithmetic number, because the mean of its divisors is an integer number (1193466).

Almost surely, 2^3978215 is an apocalyptic number.

3978215 is a deficient number, since it is larger than the sum of its proper divisors (795649).

3978215 is an equidigital number, since it uses as much as digits as its factorization.

3978215 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 795648.

The product of its digits is 15120, while the sum is 35.

The square root of 3978215 is about 1994.5463143281. The cubic root of 3978215 is about 158.4514010097.

The spelling of 3978215 in words is "three million, nine hundred seventy-eight thousand, two hundred fifteen".