78640873 has 4 divisors (see below), whose sum is σ = 80766340. Its totient is φ = 76515408.

The previous prime is 78640843. The next prime is 78640927. The reversal of 78640873 is 37804687.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 37804687 = 599 ⋅63113.

It can be written as a sum of positive squares in 2 ways, for example, as 40793769 + 37847104 = 6387^2 + 6152^2 .

It is not a de Polignac number, because 78640873 - 2⁹ = 78640361 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78640843) 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, 1062678 + ... + 1062751.

It is an arithmetic number, because the mean of its divisors is an integer number (20191585).

Almost surely, 2^78640873 is an apocalyptic number.

It is an amenable number.

78640873 is a deficient number, since it is larger than the sum of its proper divisors (2125467).

78640873 is a wasteful number, since it uses less digits than its factorization.

78640873 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2125466.

The product of its (nonzero) digits is 225792, while the sum is 43.

The square root of 78640873 is about 8867.9689331887. The cubic root of 78640873 is about 428.4328622880.

The spelling of 78640873 in words is "seventy-eight million, six hundred forty thousand, eight hundred seventy-three".