121685 has 4 divisors (see below), whose sum is σ = 146028. Its totient is φ = 97344.

The previous prime is 121661. The next prime is 121687. The reversal of 121685 is 586121.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 96721 + 24964 = 311^2 + 158^2 .

It is a cyclic number.

It is not a de Polignac number, because 121685 - 2⁶ = 121621 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 121685.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121687) 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 3 ways as a sum of consecutive naturals, for example, 12164 + ... + 12173.

It is an arithmetic number, because the mean of its divisors is an integer number (36507).

2¹²¹⁶⁸⁵ is an apocalyptic number.

It is an amenable number.

121685 is a deficient number, since it is larger than the sum of its proper divisors (24343).

121685 is an equidigital number, since it uses as much as digits as its factorization.

121685 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24342.

The product of its digits is 480, while the sum is 23.

The square root of 121685 is about 348.8337713009. The cubic root of 121685 is about 49.5540341147.

The spelling of 121685 in words is "one hundred twenty-one thousand, six hundred eighty-five".