121891855 has 4 divisors (see below), whose sum is σ = 146270232. Its totient is φ = 97513480.

The previous prime is 121891837. The next prime is 121891867. The reversal of 121891855 is 558198121.

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

It is not a de Polignac number, because 121891855 - 2¹⁹ = 121367567 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12189181 + ... + 12189190.

It is an arithmetic number, because the mean of its divisors is an integer number (36567558).

Almost surely, 2^121891855 is an apocalyptic number.

121891855 is a deficient number, since it is larger than the sum of its proper divisors (24378377).

121891855 is an equidigital number, since it uses as much as digits as its factorization.

121891855 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24378376.

The product of its digits is 28800, while the sum is 40.

The square root of 121891855 is about 11040.4644376946. The cubic root of 121891855 is about 495.8209754862.

The spelling of 121891855 in words is "one hundred twenty-one million, eight hundred ninety-one thousand, eight hundred fifty-five".