3157991 has 2 divisors, whose sum is σ = 3157992. Its totient is φ = 3157990.

The previous prime is 3157981. The next prime is 3157993. The reversal of 3157991 is 1997513.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 3157991 - 2⁶ = 3157927 is a prime.

It is a Sophie Germain prime.

Together with 3157993, 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 (3157993) 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, 1578995 + 1578996.

It is an arithmetic number, because the mean of its divisors is an integer number (1578996).

Almost surely, 2^3157991 is an apocalyptic number.

3157991 is a deficient number, since it is larger than the sum of its proper divisors (1).

3157991 is an equidigital number, since it uses as much as digits as its factorization.

3157991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8505, while the sum is 35.

The square root of 3157991 is about 1777.0737182233. The cubic root of 3157991 is about 146.7135737247.

The spelling of 3157991 in words is "three million, one hundred fifty-seven thousand, nine hundred ninety-one".