3917989 has 2 divisors, whose sum is σ = 3917990. Its totient is φ = 3917988.

The previous prime is 3917923. The next prime is 3918011. The reversal of 3917989 is 9897193.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2117025 + 1800964 = 1455^2 + 1342^2 .

It is a cyclic number.

It is not a de Polignac number, because 3917989 - 2¹¹ = 3915941 is a prime.

It is an Ulam number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (3917909) by changing a digit.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1958994 + 1958995.

It is an arithmetic number, because the mean of its divisors is an integer number (1958995).

Almost surely, 2^3917989 is an apocalyptic number.

It is an amenable number.

3917989 is a deficient number, since it is larger than the sum of its proper divisors (1).

3917989 is an equidigital number, since it uses as much as digits as its factorization.

3917989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 122472, while the sum is 46.

The square root of 3917989 is about 1979.3910679803. The cubic root of 3917989 is about 157.6477357395.

The spelling of 3917989 in words is "three million, nine hundred seventeen thousand, nine hundred eighty-nine".