121155839 has 4 divisors (see below), whose sum is σ = 138463824. Its totient is φ = 103847856.

The previous prime is 121155803. The next prime is 121155857. The reversal of 121155839 is 938551121.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 938551121 = 2879 ⋅325999.

It is a de Polignac number, because none of the positive numbers 2^k-121155839 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 121155799 and 121155808.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121155239) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8653982 + ... + 8653995.

It is an arithmetic number, because the mean of its divisors is an integer number (34615956).

Almost surely, 2^121155839 is an apocalyptic number.

121155839 is a deficient number, since it is larger than the sum of its proper divisors (17307985).

121155839 is an equidigital number, since it uses as much as digits as its factorization.

121155839 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17307984.

The product of its digits is 10800, while the sum is 35.

The square root of 121155839 is about 11007.0813115921. The cubic root of 121155839 is about 494.8209929886.

The spelling of 121155839 in words is "one hundred twenty-one million, one hundred fifty-five thousand, eight hundred thirty-nine".