82991 has 4 divisors (see below), whose sum is σ = 85272. Its totient is φ = 80712.

The previous prime is 82981. The next prime is 82997. The reversal of 82991 is 19928.

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 82991 - 2¹⁰ = 81967 is a prime.

It is a Duffinian number.

It is a plaindrome in base 14.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (82997) 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, 1085 + ... + 1158.

It is an arithmetic number, because the mean of its divisors is an integer number (21318).

2⁸²⁹⁹¹ is an apocalyptic number.

82991 is a deficient number, since it is larger than the sum of its proper divisors (2281).

82991 is a wasteful number, since it uses less digits than its factorization.

82991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2280.

The product of its digits is 1296, while the sum is 29.

The square root of 82991 is about 288.0815856663. The cubic root of 82991 is about 43.6191300055.

The spelling of 82991 in words is "eighty-two thousand, nine hundred ninety-one".