78878380806857 has 2 divisors, whose sum is σ = 78878380806858. Its totient is φ = 78878380806856.

The previous prime is 78878380806829. The next prime is 78878380806941. The reversal of 78878380806857 is 75860808387887.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 65962270784656 + 12916110022201 = 8121716^2 + 3593899^2 .

It is a cyclic number.

It is not a de Polignac number, because 78878380806857 - 2¹² = 78878380802761 is a prime.

It is not a weakly prime, because it can be changed into another prime (78878380806817) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39439190403428 + 39439190403429.

It is an arithmetic number, because the mean of its divisors is an integer number (39439190403429).

Almost surely, 2^{78878380806857} is an apocalyptic number.

It is an amenable number.

78878380806857 is a deficient number, since it is larger than the sum of its proper divisors (1).

78878380806857 is an equidigital number, since it uses as much as digits as its factorization.

78878380806857 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8092385280, while the sum is 83.

The spelling of 78878380806857 in words is "seventy-eight trillion, eight hundred seventy-eight billion, three hundred eighty million, eight hundred six thousand, eight hundred fifty-seven".