121781456777 has 2 divisors, whose sum is σ = 121781456778. Its totient is φ = 121781456776.

The previous prime is 121781456773. The next prime is 121781456789. The reversal of 121781456777 is 777654187121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 91234806601 + 30546650176 = 302051^2 + 174776^2 .

It is a cyclic number.

It is not a de Polignac number, because 121781456777 - 2² = 121781456773 is a prime.

It is not a weakly prime, because it can be changed into another prime (121781456773) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60890728388 + 60890728389.

It is an arithmetic number, because the mean of its divisors is an integer number (60890728389).

Almost surely, 2^121781456777 is an apocalyptic number.

It is an amenable number.

121781456777 is a deficient number, since it is larger than the sum of its proper divisors (1).

121781456777 is an equidigital number, since it uses as much as digits as its factorization.

121781456777 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4609920, while the sum is 56.

The spelling of 121781456777 in words is "one hundred twenty-one billion, seven hundred eighty-one million, four hundred fifty-six thousand, seven hundred seventy-seven".