78166866187 has 4 divisors (see below), whose sum is σ = 78245743936. Its totient is φ = 78087988440.

The previous prime is 78166866161. The next prime is 78166866199.

78166866187 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 a de Polignac number, because none of the positive numbers 2^k-78166866187 is a prime.

It is a super-2 number, since 2×78166866187² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78166866287) 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, 39437388 + ... + 39439369.

It is an arithmetic number, because the mean of its divisors is an integer number (19561435984).

Almost surely, 2^78166866187 is an apocalyptic number.

78166866187 is a deficient number, since it is larger than the sum of its proper divisors (78877749).

78166866187 is an equidigital number, since it uses as much as digits as its factorization.

78166866187 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 78877748.

The product of its digits is 32514048, while the sum is 64.

The spelling of 78166866187 in words is "seventy-eight billion, one hundred sixty-six million, eight hundred sixty-six thousand, one hundred eighty-seven".