78840813 has 8 divisors (see below), whose sum is σ = 105434368. Its totient is φ = 52403904.

The previous prime is 78840809. The next prime is 78840833. The reversal of 78840813 is 31804887.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 78840813 - 2² = 78840809 is a prime.

It is a Duffinian number.

It is a plaindrome in base 13.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78840833) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 37981 + ... + 40002.

It is an arithmetic number, because the mean of its divisors is an integer number (13179296).

Almost surely, 2^78840813 is an apocalyptic number.

It is an amenable number.

78840813 is a deficient number, since it is larger than the sum of its proper divisors (26593555).

78840813 is a wasteful number, since it uses less digits than its factorization.

78840813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 78323.

The product of its (nonzero) digits is 43008, while the sum is 39.

The square root of 78840813 is about 8879.2349332586. The cubic root of 78840813 is about 428.7956438358.

The spelling of 78840813 in words is "seventy-eight million, eight hundred forty thousand, eight hundred thirteen".