121781456783 has 16 divisors (see below), whose sum is σ = 146514923520. Its totient is φ = 98882837856.

The previous prime is 121781456777. The next prime is 121781456789. The reversal of 121781456783 is 387654187121.

It is a happy number.

It is a Cunningham number, because it is equal to 348972²-1.

It is an interprime number because it is at equal distance from previous prime (121781456777) and next prime (121781456789).

It is a cyclic number.

It is not a de Polignac number, because 121781456783 - 2²⁴ = 121764679567 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121781456789) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2417885 + ... + 2467737.

It is an arithmetic number, because the mean of its divisors is an integer number (9157182720).

Almost surely, 2^121781456783 is an apocalyptic number.

121781456783 is a deficient number, since it is larger than the sum of its proper divisors (24733466737).

121781456783 is a wasteful number, since it uses less digits than its factorization.

121781456783 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 68246.

The product of its digits is 2257920, while the sum is 53.

The spelling of 121781456783 in words is "one hundred twenty-one billion, seven hundred eighty-one million, four hundred fifty-six thousand, seven hundred eighty-three".