3978641 has 2 divisors, whose sum is σ = 3978642.
Its totient is φ = 3978640.
The previous prime is 3978593. The next prime is 3978643. The reversal of 3978641 is 1468793.
It is a strong prime.
It can be written as a sum of positive squares in only one way, i.e., 3940225 + 38416 = 1985^2 + 196^2
It is a cyclic number.
It is a de Polignac number, because none of the positive numbers 2k-3978641 is a prime.
It is a Sophie Germain prime.
Together with 3978643, it forms a pair of twin primes.
It is a Chen prime.
It is a Curzon number.
It is a junction number, because it is equal to n+sod(n) for n = 3978595 and 3978604.
It is not a weakly prime, because it can be changed into another prime (3978643) by changing a digit.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1989320 + 1989321.
It is an arithmetic number, because the mean of its divisors is an integer number (1989321).
Almost surely, 23978641 is an apocalyptic number.
It is an amenable number.
3978641 is a deficient number, since it is larger than the sum of its proper divisors (1).
3978641 is an equidigital number, since it uses as much as digits as its factorization.
3978641 is an evil number, because the sum of its binary digits is even.
The product of its digits is 36288, while the sum is 38.
The square root of 3978641 is about 1994.6531026722.
The cubic root of 3978641 is about 158.4570566356.
The spelling of 3978641 in words is "three million, nine hundred seventy-eight thousand, six hundred forty-one".