40691 has 4 divisors (see below), whose sum is σ = 46512. Its totient is φ = 34872.

The previous prime is 40639. The next prime is 40693. The reversal of 40691 is 19604.

40691 is nontrivially palindromic in base 6.

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

It is a cyclic number.

It is not a de Polignac number, because 40691 - 2⁶ = 40627 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (40693) 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, 2900 + ... + 2913.

It is an arithmetic number, because the mean of its divisors is an integer number (11628).

2⁴⁰⁶⁹¹ is an apocalyptic number.

40691 is a deficient number, since it is larger than the sum of its proper divisors (5821).

40691 is an equidigital number, since it uses as much as digits as its factorization.

40691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5820.

The product of its (nonzero) digits is 216, while the sum is 20.

The square root of 40691 is about 201.7201031132. The cubic root of 40691 is about 34.3953279215.

The spelling of 40691 in words is "forty thousand, six hundred ninety-one".