78315871 has 4 divisors (see below), whose sum is σ = 78457032. Its totient is φ = 78174712.

The previous prime is 78315869. The next prime is 78315883. The reversal of 78315871 is 17851387.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 17851387 = 2131 ⋅8377.

It is a cyclic number.

It is not a de Polignac number, because 78315871 - 2¹ = 78315869 is a prime.

It is a super-2 number, since 2×78315871² = 12266751300977282, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78315841) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 69745 + ... + 70858.

It is an arithmetic number, because the mean of its divisors is an integer number (19614258).

Almost surely, 2^78315871 is an apocalyptic number.

78315871 is a deficient number, since it is larger than the sum of its proper divisors (141161).

78315871 is a wasteful number, since it uses less digits than its factorization.

78315871 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 141160.

The product of its digits is 47040, while the sum is 40.

The square root of 78315871 is about 8849.6254723011. The cubic root of 78315871 is about 427.8418473378.

The spelling of 78315871 in words is "seventy-eight million, three hundred fifteen thousand, eight hundred seventy-one".