29991 has 8 divisors (see below), whose sum is σ = 43120. Its totient is φ = 18432.

The previous prime is 29989. The next prime is 30011. The reversal of 29991 is 19992.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 29991 - 2¹ = 29989 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (29921) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 346 + ... + 423.

It is an arithmetic number, because the mean of its divisors is an integer number (5390).

2²⁹⁹⁹¹ is an apocalyptic number.

29991 is a deficient number, since it is larger than the sum of its proper divisors (13129).

29991 is a wasteful number, since it uses less digits than its factorization.

29991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 785.

The product of its digits is 1458, while the sum is 30.

The square root of 29991 is about 173.1790980459. The cubic root of 29991 is about 31.0692175163.

Subtracting from 29991 its reverse (19992), we obtain a palindrome (9999).

The spelling of 29991 in words is "twenty-nine thousand, nine hundred ninety-one".