78706619209 has 3 divisors (see below), whose sum is σ = 78706899757. Its totient is φ = 78706338662.

The previous prime is 78706619171. The next prime is 78706619213. The reversal of 78706619209 is 90291660787.

The square root of 78706619209 is 280547.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is not a de Polignac number, because 78706619209 - 2⁷ = 78706619081 is a prime.

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 78706619209.

It is not an unprimeable number, because it can be changed into a prime (78706619009) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 140274 + ... + 420820.

Almost surely, 2^78706619209 is an apocalyptic number.

78706619209 is the 280547-th square number.

78706619209 is the 140274-th centered octagonal number.

It is an amenable number.

78706619209 is a deficient number, since it is larger than the sum of its proper divisors (280548).

78706619209 is an frugal number, since it uses more digits than its factorization.

78706619209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 561094 (or 280547 counting only the distinct ones).

The product of its (nonzero) digits is 2286144, while the sum is 55.

The spelling of 78706619209 in words is "seventy-eight billion, seven hundred six million, six hundred nineteen thousand, two hundred nine".