78320057 has 2 divisors, whose sum is σ = 78320058. Its totient is φ = 78320056.

The previous prime is 78320017. The next prime is 78320059. The reversal of 78320057 is 75002387.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 77018176 + 1301881 = 8776^2 + 1141^2 .

It is an emirp because it is prime and its reverse (75002387) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 78320057 - 2¹⁸ = 78057913 is a prime.

It is a super-2 number, since 2×78320057² = 12268062656966498, which contains 22 as substring.

Together with 78320059, it forms a pair of twin primes.

It is a Chen prime.

It is equal to p_4577117 and since 78320057 and 4577117 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (78320059) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39160028 + 39160029.

It is an arithmetic number, because the mean of its divisors is an integer number (39160029).

Almost surely, 2^78320057 is an apocalyptic number.

It is an amenable number.

78320057 is a deficient number, since it is larger than the sum of its proper divisors (1).

78320057 is an equidigital number, since it uses as much as digits as its factorization.

78320057 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 11760, while the sum is 32.

The square root of 78320057 is about 8849.8619763248. The cubic root of 78320057 is about 427.8494699480.

The spelling of 78320057 in words is "seventy-eight million, three hundred twenty thousand, fifty-seven".