3913991 has 2 divisors, whose sum is σ = 3913992. Its totient is φ = 3913990.

The previous prime is 3913969. The next prime is 3913993. The reversal of 3913991 is 1993193.

It is a happy number.

It is a strong prime.

It is an emirp because it is prime and its reverse (1993193) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 3913991 - 2¹⁸ = 3651847 is a prime.

It is a Sophie Germain prime.

Together with 3913993, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (3913993) 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, 1956995 + 1956996.

It is an arithmetic number, because the mean of its divisors is an integer number (1956996).

Almost surely, 2^3913991 is an apocalyptic number.

3913991 is a deficient number, since it is larger than the sum of its proper divisors (1).

3913991 is an equidigital number, since it uses as much as digits as its factorization.

3913991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6561, while the sum is 35.

The square root of 3913991 is about 1978.3809036685. The cubic root of 3913991 is about 157.5940951132.

It can be divided in two parts, 3913 and 991, that multiplied together give a palindrome (3877783).

The spelling of 3913991 in words is "three million, nine hundred thirteen thousand, nine hundred ninety-one".