78205456309 has 2 divisors, whose sum is σ = 78205456310. Its totient is φ = 78205456308.

The previous prime is 78205456253. The next prime is 78205456327. The reversal of 78205456309 is 90365450287.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 62961850084 + 15243606225 = 250922^2 + 123465^2 .

It is a cyclic number.

It is not a de Polignac number, because 78205456309 - 2²⁵ = 78171901877 is a prime.

It is a super-2 number, since 2×78205456309² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78205456009) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39102728154 + 39102728155.

It is an arithmetic number, because the mean of its divisors is an integer number (39102728155).

Almost surely, 2^78205456309 is an apocalyptic number.

It is an amenable number.

78205456309 is a deficient number, since it is larger than the sum of its proper divisors (1).

78205456309 is an equidigital number, since it uses as much as digits as its factorization.

78205456309 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1814400, while the sum is 49.

The spelling of 78205456309 in words is "seventy-eight billion, two hundred five million, four hundred fifty-six thousand, three hundred nine".