78718457 has 2 divisors, whose sum is σ = 78718458. Its totient is φ = 78718456.

The previous prime is 78718427. The next prime is 78718459. The reversal of 78718457 is 75481787.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 67502656 + 11215801 = 8216^2 + 3349^2 .

It is a cyclic number.

It is not a de Polignac number, because 78718457 - 2¹⁴ = 78702073 is a prime.

Together with 78718459, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (78718459) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39359228 + 39359229.

It is an arithmetic number, because the mean of its divisors is an integer number (39359229).

Almost surely, 2^78718457 is an apocalyptic number.

It is an amenable number.

78718457 is a deficient number, since it is larger than the sum of its proper divisors (1).

78718457 is an equidigital number, since it uses as much as digits as its factorization.

78718457 is an evil number, because the sum of its binary digits is even.

The product of its digits is 439040, while the sum is 47.

The square root of 78718457 is about 8872.3422499360. The cubic root of 78718457 is about 428.5737076651.

The spelling of 78718457 in words is "seventy-eight million, seven hundred eighteen thousand, four hundred fifty-seven".