78684997 has 2 divisors, whose sum is σ = 78684998. Its totient is φ = 78684996.

The previous prime is 78684979. The next prime is 78685049. The reversal of 78684997 is 79948687.

It is a happy number.

Together with previous prime (78684979) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 44742721 + 33942276 = 6689^2 + 5826^2 .

It is a cyclic number.

It is not a de Polignac number, because 78684997 - 2¹¹ = 78682949 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78684967) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39342498 + 39342499.

It is an arithmetic number, because the mean of its divisors is an integer number (39342499).

Almost surely, 2^78684997 is an apocalyptic number.

It is an amenable number.

78684997 is a deficient number, since it is larger than the sum of its proper divisors (1).

78684997 is an equidigital number, since it uses as much as digits as its factorization.

78684997 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6096384, while the sum is 58.

The square root of 78684997 is about 8870.4564144130. The cubic root of 78684997 is about 428.5129760016.

The spelling of 78684997 in words is "seventy-eight million, six hundred eighty-four thousand, nine hundred ninety-seven".