78395813 has 4 divisors (see below), whose sum is σ = 80307948. Its totient is φ = 76483680.

The previous prime is 78395809. The next prime is 78395819. The reversal of 78395813 is 31859387.

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: 31859387 = 7 ⋅4551341.

It can be written as a sum of positive squares in 2 ways, for example, as 13786369 + 64609444 = 3713^2 + 8038^2 .

It is a cyclic number.

It is not a de Polignac number, because 78395813 - 2² = 78395809 is a prime.

It is a super-5 number, since 5×78395813⁵ (a number of 41 digits) contains 55555 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78395819) 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, 956006 + ... + 956087.

It is an arithmetic number, because the mean of its divisors is an integer number (20076987).

Almost surely, 2^78395813 is an apocalyptic number.

It is an amenable number.

78395813 is a deficient number, since it is larger than the sum of its proper divisors (1912135).

78395813 is a wasteful number, since it uses less digits than its factorization.

78395813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1912134.

The product of its digits is 181440, while the sum is 44.

The square root of 78395813 is about 8854.1410085903. The cubic root of 78395813 is about 427.9873729789.

The spelling of 78395813 in words is "seventy-eight million, three hundred ninety-five thousand, eight hundred thirteen".