121917 has 4 divisors (see below), whose sum is σ = 162560. Its totient is φ = 81276.

The previous prime is 121909. The next prime is 121921. The reversal of 121917 is 719121.

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.

It is not a de Polignac number, because 121917 - 2³ = 121909 is a prime.

It is an Ulam number.

It is a D-number.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 121893 and 121902.

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 121917.

It is not an unprimeable number, because it can be changed into a prime (121937) 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, 20317 + ... + 20322.

It is an arithmetic number, because the mean of its divisors is an integer number (40640).

2¹²¹⁹¹⁷ is an apocalyptic number.

It is an amenable number.

121917 is a deficient number, since it is larger than the sum of its proper divisors (40643).

121917 is an equidigital number, since it uses as much as digits as its factorization.

121917 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40642.

The product of its digits is 126, while the sum is 21.

The square root of 121917 is about 349.1661495621. The cubic root of 121917 is about 49.5855067349.

The spelling of 121917 in words is "one hundred twenty-one thousand, nine hundred seventeen".