78705779 has 2 divisors, whose sum is σ = 78705780. Its totient is φ = 78705778.

The previous prime is 78705761. The next prime is 78705811. The reversal of 78705779 is 97750787.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-78705779 is a prime.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (78705749) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39352889 + 39352890.

It is an arithmetic number, because the mean of its divisors is an integer number (39352890).

Almost surely, 2^78705779 is an apocalyptic number.

78705779 is a deficient number, since it is larger than the sum of its proper divisors (1).

78705779 is an equidigital number, since it uses as much as digits as its factorization.

78705779 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 864360, while the sum is 50.

The square root of 78705779 is about 8871.6277536876. The cubic root of 78705779 is about 428.5506984523.

The spelling of 78705779 in words is "seventy-eight million, seven hundred five thousand, seven hundred seventy-nine".