78778874171 has 4 divisors (see below), whose sum is σ = 79016877144. Its totient is φ = 78540871200.

The previous prime is 78778874159. The next prime is 78778874261. The reversal of 78778874171 is 17147887787.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 17147887787 = 2309 ⋅7426543.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-78778874171 is a prime.

It is a super-2 number, since 2×78778874171² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 78778874098 and 78778874107.

It is not an unprimeable number, because it can be changed into a prime (78778874101) 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, 119000990 + ... + 119001651.

It is an arithmetic number, because the mean of its divisors is an integer number (19754219286).

Almost surely, 2^78778874171 is an apocalyptic number.

78778874171 is a deficient number, since it is larger than the sum of its proper divisors (238002973).

78778874171 is a wasteful number, since it uses less digits than its factorization.

78778874171 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 238002972.

The product of its digits is 34420736, while the sum is 65.

The spelling of 78778874171 in words is "seventy-eight billion, seven hundred seventy-eight million, eight hundred seventy-four thousand, one hundred seventy-one".