98991 has 12 divisors (see below), whose sum is σ = 151632. Its totient is φ = 62016.

The previous prime is 98981. The next prime is 98993. The reversal of 98991 is 19989.

It is not a de Polignac number, because 98991 - 2⁶ = 98927 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (98993) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 171 + ... + 476.

It is an arithmetic number, because the mean of its divisors is an integer number (12636).

2⁹⁸⁹⁹¹ is an apocalyptic number.

98991 is a deficient number, since it is larger than the sum of its proper divisors (52641).

98991 is a wasteful number, since it uses less digits than its factorization.

98991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 670 (or 667 counting only the distinct ones).

The product of its digits is 5832, while the sum is 36.

The square root of 98991 is about 314.6283521871. The cubic root of 98991 is about 46.2592482115.

It can be divided in two parts, 98 and 991, that added together give a square (1089 = 33²).

The spelling of 98991 in words is "ninety-eight thousand, nine hundred ninety-one".