78205715805187 has 4 divisors (see below), whose sum is σ = 81605964318480. Its totient is φ = 74805467291896.

The previous prime is 78205715805157. The next prime is 78205715805221. The reversal of 78205715805187 is 78150851750287.

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 78205715805187 - 2⁴³ = 69409622782979 is a prime.

It is a super-2 number, since 2×78205715805187² (a number of 29 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78205715805157) 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, 1700124256612 + ... + 1700124256657.

It is an arithmetic number, because the mean of its divisors is an integer number (20401491079620).

Almost surely, 2^{78205715805187} is an apocalyptic number.

78205715805187 is a deficient number, since it is larger than the sum of its proper divisors (3400248513293).

78205715805187 is a wasteful number, since it uses less digits than its factorization.

78205715805187 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3400248513292.

The product of its (nonzero) digits is 43904000, while the sum is 64.

The spelling of 78205715805187 in words is "seventy-eight trillion, two hundred five billion, seven hundred fifteen million, eight hundred five thousand, one hundred eighty-seven".