117581 has 4 divisors (see below), whose sum is σ = 118272. Its totient is φ = 116892.

The previous prime is 117577. The next prime is 117617. The reversal of 117581 is 185711.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 117581 - 2² = 117577 is a prime.

It is a super-2 number, since 2×117581² = 27650583122, which contains 22 as substring.

It is a Duffinian number.

It is a nialpdrome in base 7.

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 117581.

It is not an unprimeable number, because it can be changed into a prime (117511) 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, 116 + ... + 498.

It is an arithmetic number, because the mean of its divisors is an integer number (29568).

2¹¹⁷⁵⁸¹ is an apocalyptic number.

It is an amenable number.

117581 is a deficient number, since it is larger than the sum of its proper divisors (691).

117581 is an equidigital number, since it uses as much as digits as its factorization.

117581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 690.

The product of its digits is 280, while the sum is 23.

The square root of 117581 is about 342.9008603080. The cubic root of 117581 is about 48.9905576697.

The spelling of 117581 in words is "one hundred seventeen thousand, five hundred eighty-one".