3979861 has 2 divisors, whose sum is σ = 3979862. Its totient is φ = 3979860.

The previous prime is 3979849. The next prime is 3979883. The reversal of 3979861 is 1689793.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2047761 + 1932100 = 1431^2 + 1390^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-3979861 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (3979891) 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 as a sum of consecutive naturals, namely, 1989930 + 1989931.

It is an arithmetic number, because the mean of its divisors is an integer number (1989931).

Almost surely, 2^3979861 is an apocalyptic number.

It is an amenable number.

3979861 is a deficient number, since it is larger than the sum of its proper divisors (1).

3979861 is an equidigital number, since it uses as much as digits as its factorization.

3979861 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 81648, while the sum is 43.

The square root of 3979861 is about 1994.9588968197. The cubic root of 3979861 is about 158.4732512653.

The spelling of 3979861 in words is "three million, nine hundred seventy-nine thousand, eight hundred sixty-one".