78185897 has 2 divisors, whose sum is σ = 78185898. Its totient is φ = 78185896.

The previous prime is 78185879. The next prime is 78185903. The reversal of 78185897 is 79858187.

It is a happy number.

Together with previous prime (78185879) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 58079641 + 20106256 = 7621^2 + 4484^2 .

It is a cyclic number.

It is not a de Polignac number, because 78185897 - 2¹⁸ = 77923753 is a prime.

It is a super-2 number, since 2×78185897² = 12226068979389218, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (78185857) 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, 39092948 + 39092949.

It is an arithmetic number, because the mean of its divisors is an integer number (39092949).

Almost surely, 2^78185897 is an apocalyptic number.

It is an amenable number.

78185897 is a deficient number, since it is larger than the sum of its proper divisors (1).

78185897 is an equidigital number, since it uses as much as digits as its factorization.

78185897 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1128960, while the sum is 53.

The square root of 78185897 is about 8842.2789483255. The cubic root of 78185897 is about 427.6050323870.

The spelling of 78185897 in words is "seventy-eight million, one hundred eighty-five thousand, eight hundred ninety-seven".