121781456778 has 16 divisors (see below), whose sum is σ = 243600887520. Its totient is φ = 40587489936.

The previous prime is 121781456777. The next prime is 121781456789. The reversal of 121781456778 is 877654187121.

121781456778 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (121781456773) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1540473 + ... + 1617596.

It is an arithmetic number, because the mean of its divisors is an integer number (15225055470).

Almost surely, 2^121781456778 is an apocalyptic number.

121781456778 is an abundant number, since it is smaller than the sum of its proper divisors (121819430742).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

121781456778 is a wasteful number, since it uses less digits than its factorization.

121781456778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3164501.

The product of its digits is 5268480, while the sum is 57.

The spelling of 121781456778 in words is "one hundred twenty-one billion, seven hundred eighty-one million, four hundred fifty-six thousand, seven hundred seventy-eight".