78553661693 has 16 divisors (see below), whose sum is σ = 94286848320. Its totient is φ = 64653831936.

The previous prime is 78553661689. The next prime is 78553661713. The reversal of 78553661693 is 39616635587.

It is a cyclic number.

It is not a de Polignac number, because 78553661693 - 2² = 78553661689 is a prime.

It is a Smith number, since the sum of its digits (59) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78553661393) 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 in 15 ways as a sum of consecutive naturals, for example, 9349655 + ... + 9358052.

It is an arithmetic number, because the mean of its divisors is an integer number (5892928020).

Almost surely, 2^78553661693 is an apocalyptic number.

It is an amenable number.

78553661693 is a deficient number, since it is larger than the sum of its proper divisors (15733186627).

78553661693 is a wasteful number, since it uses less digits than its factorization.

78553661693 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18707756.

The product of its digits is 24494400, while the sum is 59.

The spelling of 78553661693 in words is "seventy-eight billion, five hundred fifty-three million, six hundred sixty-one thousand, six hundred ninety-three".