121345787891 has 24 divisors (see below), whose sum is σ = 132139701360. Its totient is φ = 111375931392.

The previous prime is 121345787879. The next prime is 121345787897. The reversal of 121345787891 is 198787543121.

It is a de Polignac number, because none of the positive numbers 2^k-121345787891 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (121345787897) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1845320 + ... + 1909946.

It is an arithmetic number, because the mean of its divisors is an integer number (5505820890).

Almost surely, 2^121345787891 is an apocalyptic number.

121345787891 is a deficient number, since it is larger than the sum of its proper divisors (10793913469).

121345787891 is an equidigital number, since it uses as much as digits as its factorization.

121345787891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 64823 (or 64806 counting only the distinct ones).

The product of its digits is 3386880, while the sum is 56.

The spelling of 121345787891 in words is "one hundred twenty-one billion, three hundred forty-five million, seven hundred eighty-seven thousand, eight hundred ninety-one".