78505791653 has 2 divisors, whose sum is σ = 78505791654. Its totient is φ = 78505791652.

The previous prime is 78505791643. The next prime is 78505791691. The reversal of 78505791653 is 35619750587.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 75568910404 + 2936881249 = 274898^2 + 54193^2 .

It is a cyclic number.

It is not a de Polignac number, because 78505791653 - 2¹⁴ = 78505775269 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78505791643) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39252895826 + 39252895827.

It is an arithmetic number, because the mean of its divisors is an integer number (39252895827).

Almost surely, 2^78505791653 is an apocalyptic number.

It is an amenable number.

78505791653 is a deficient number, since it is larger than the sum of its proper divisors (1).

78505791653 is an equidigital number, since it uses as much as digits as its factorization.

78505791653 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7938000, while the sum is 56.

The spelling of 78505791653 in words is "seventy-eight billion, five hundred five million, seven hundred ninety-one thousand, six hundred fifty-three".