78106809 has 16 divisors (see below), whose sum is σ = 116029440. Its totient is φ = 46329360.

The previous prime is 78106801. The next prime is 78106811. The reversal of 78106809 is 90860187.

It is not a de Polignac number, because 78106809 - 2³ = 78106801 is a prime.

It is a super-2 number, since 2×78106809² = 12201347224324962, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (78106801) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 23629 + ... + 26730.

It is an arithmetic number, because the mean of its divisors is an integer number (7251840).

Almost surely, 2^78106809 is an apocalyptic number.

It is an amenable number.

78106809 is a deficient number, since it is larger than the sum of its proper divisors (37922631).

78106809 is a wasteful number, since it uses less digits than its factorization.

78106809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50420.

The product of its (nonzero) digits is 24192, while the sum is 39.

The square root of 78106809 is about 8837.8056665668. The cubic root of 78106809 is about 427.4608041763.

The spelling of 78106809 in words is "seventy-eight million, one hundred six thousand, eight hundred nine".