121917819171 has 4 divisors (see below), whose sum is σ = 162557092232. Its totient is φ = 81278546112.

The previous prime is 121917819169. The next prime is 121917819211. The reversal of 121917819171 is 171918719121.

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

It is not a de Polignac number, because 121917819171 - 2¹ = 121917819169 is a prime.

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 121917819171.

It is not an unprimeable number, because it can be changed into a prime (121917819131) 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, 20319636526 + ... + 20319636531.

It is an arithmetic number, because the mean of its divisors is an integer number (40639273058).

Almost surely, 2^121917819171 is an apocalyptic number.

121917819171 is a deficient number, since it is larger than the sum of its proper divisors (40639273061).

121917819171 is an equidigital number, since it uses as much as digits as its factorization.

121917819171 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40639273060.

The product of its digits is 63504, while the sum is 48.

The spelling of 121917819171 in words is "one hundred twenty-one billion, nine hundred seventeen million, eight hundred nineteen thousand, one hundred seventy-one".