117981 has 6 divisors (see below), whose sum is σ = 170430. Its totient is φ = 78648.

The previous prime is 117979. The next prime is 117989. The reversal of 117981 is 189711.

It can be written as a sum of positive squares in only one way, i.e., 95481 + 22500 = 309^2 + 150^2 .

It is not a de Polignac number, because 117981 - 2¹ = 117979 is a prime.

It is a super-2 number, since 2×117981² = 27839032722, which contains 22 as substring.

It is a plaindrome in base 16.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 117981.

It is not an unprimeable number, because it can be changed into a prime (117989) 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 5 ways as a sum of consecutive naturals, for example, 6546 + ... + 6563.

It is an arithmetic number, because the mean of its divisors is an integer number (28405).

2¹¹⁷⁹⁸¹ is an apocalyptic number.

It is an amenable number.

117981 is a deficient number, since it is larger than the sum of its proper divisors (52449).

117981 is a wasteful number, since it uses less digits than its factorization.

117981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13115 (or 13112 counting only the distinct ones).

The product of its digits is 504, while the sum is 27.

The square root of 117981 is about 343.4836240638. The cubic root of 117981 is about 49.0460486176.

The spelling of 117981 in words is "one hundred seventeen thousand, nine hundred eighty-one".