78778188187787 has 4 divisors (see below), whose sum is σ = 85939841659416. Its totient is φ = 71616534716160.

The previous prime is 78778188187681. The next prime is 78778188187789.

It is a happy number.

78778188187787 is nontrivially palindromic in base 10.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 78778188187787 - 2¹⁸ = 78778187925643 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 78778188187696 and 78778188187705.

It is not an unprimeable number, because it can be changed into a prime (78778188187789) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3580826735798 + ... + 3580826735819.

It is an arithmetic number, because the mean of its divisors is an integer number (21484960414854).

Almost surely, 2^{78778188187787} is an apocalyptic number.

78778188187787 is a deficient number, since it is larger than the sum of its proper divisors (7161653471629).

78778188187787 is a wasteful number, since it uses less digits than its factorization.

78778188187787 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7161653471628.

The product of its digits is 30840979456, while the sum is 92.

The spelling of 78778188187787 in words is "seventy-eight trillion, seven hundred seventy-eight billion, one hundred eighty-eight million, one hundred eighty-seven thousand, seven hundred eighty-seven".