78809894361 has 81 divisors (see below), whose sum is σ = 128555214879.
Its totient is φ = 46489053600.
The previous prime is 78809894351. The next prime is 78809894369. The reversal of 78809894361 is 16349890887.
The square root of 78809894361 is 280731.
It is a perfect power (a square), and thus also a powerful number.
It can be written as a sum of positive squares in only one way, i.e., 868421961 + 77941472400 = 29469^2 + 279180^2
It is not a de Polignac number, because 78809894361 - 211 = 78809892313 is a prime.
It is not an unprimeable number, because it can be changed into a prime (78809894369) by changing a digit.
It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 435413691 + ... + 435413871.
Almost surely, 278809894361 is an apocalyptic number.
78809894361 is the 280731-st square number.
78809894361 is the 140366-th centered octagonal number.
It is an amenable number.
78809894361 is a deficient number, since it is larger than the sum of its proper divisors (49745320518).
78809894361 is a wasteful number, since it uses less digits than its factorization.
78809894361 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 484 (or 242 counting only the distinct ones).
The product of its (nonzero) digits is 20901888, while the sum is 63.
The spelling of 78809894361 in words is "seventy-eight billion, eight hundred nine million, eight hundred ninety-four thousand, three hundred sixty-one".