371991 has 4 divisors (see below), whose sum is σ = 495992. Its totient is φ = 247992.

The previous prime is 371981. The next prime is 371999. The reversal of 371991 is 199173.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 371991 - 2⁶ = 371927 is a prime.

It is a D-number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (371999) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 61996 + ... + 62001.

It is an arithmetic number, because the mean of its divisors is an integer number (123998).

2³⁷¹⁹⁹¹ is an apocalyptic number.

371991 is a deficient number, since it is larger than the sum of its proper divisors (124001).

371991 is a wasteful number, since it uses less digits than its factorization.

371991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 124000.

The product of its digits is 1701, while the sum is 30.

The square root of 371991 is about 609.9106491938. The cubic root of 371991 is about 71.9190834795.

The spelling of 371991 in words is "three hundred seventy-one thousand, nine hundred ninety-one".