3978649 has 4 divisors (see below), whose sum is σ = 4019764. Its totient is φ = 3937536.

The previous prime is 3978643. The next prime is 3978659. The reversal of 3978649 is 9468793.

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 2433600 + 1545049 = 1560^2 + 1243^2 .

It is a cyclic number.

It is not a de Polignac number, because 3978649 - 2³ = 3978641 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 3978599 and 3978608.

It is not an unprimeable number, because it can be changed into a prime (3978641) 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, 20412 + ... + 20605.

It is an arithmetic number, because the mean of its divisors is an integer number (1004941).

Almost surely, 2^3978649 is an apocalyptic number.

It is an amenable number.

3978649 is a deficient number, since it is larger than the sum of its proper divisors (41115).

3978649 is an equidigital number, since it uses as much as digits as its factorization.

3978649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41114.

The product of its digits is 326592, while the sum is 46.

The square root of 3978649 is about 1994.6551080325. The cubic root of 3978649 is about 158.4571628407.

The spelling of 3978649 in words is "three million, nine hundred seventy-eight thousand, six hundred forty-nine".