78643650081 has 4 divisors (see below), whose sum is σ = 104858200112. Its totient is φ = 52429100052.

The previous prime is 78643650073. The next prime is 78643650091. The reversal of 78643650081 is 18005634687.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 18005634687 = 3 ⋅6001878229.

It is not a de Polignac number, because 78643650081 - 2³ = 78643650073 is a prime.

It is a super-2 number, since 2×78643650081² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 78643650081.

It is not an unprimeable number, because it can be changed into a prime (78643650011) 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, 13107275011 + ... + 13107275016.

It is an arithmetic number, because the mean of its divisors is an integer number (26214550028).

Almost surely, 2^78643650081 is an apocalyptic number.

It is an amenable number.

78643650081 is a deficient number, since it is larger than the sum of its proper divisors (26214550031).

78643650081 is a wasteful number, since it uses less digits than its factorization.

78643650081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26214550030.

The product of its (nonzero) digits is 967680, while the sum is 48.

The spelling of 78643650081 in words is "seventy-eight billion, six hundred forty-three million, six hundred fifty thousand, eighty-one".