40191 has 4 divisors (see below), whose sum is σ = 53592. Its totient is φ = 26792.

The previous prime is 40189. The next prime is 40193. The reversal of 40191 is 19104.

40191 is nontrivially palindromic in base 9.

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

It is an interprime number because it is at equal distance from previous prime (40189) and next prime (40193).

It is a cyclic number.

It is not a de Polignac number, because 40191 - 2¹ = 40189 is a prime.

It is a D-number.

It is a plaindrome in base 16.

It is a self number, because there is not a number n which added to its sum of digits gives 40191.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (40193) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6696 + ... + 6701.

It is an arithmetic number, because the mean of its divisors is an integer number (13398).

2⁴⁰¹⁹¹ is an apocalyptic number.

40191 is a deficient number, since it is larger than the sum of its proper divisors (13401).

40191 is a wasteful number, since it uses less digits than its factorization.

40191 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13400.

The product of its (nonzero) digits is 36, while the sum is 15.

The square root of 40191 is about 200.4769313412. The cubic root of 40191 is about 34.2538667558.

Adding to 40191 its reverse (19104), we get a palindrome (59295).

It can be divided in two parts, 40 and 191, that added together give a triangular number (231 = T₂₁).

The spelling of 40191 in words is "forty thousand, one hundred ninety-one".