70809 has 4 divisors (see below), whose sum is σ = 94416. Its totient is φ = 47204.

The previous prime is 70793. The next prime is 70823. The reversal of 70809 is 90807.

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: 90807 = 3 ⋅30269.

It is a cyclic number.

It is not a de Polignac number, because 70809 - 2⁴ = 70793 is a prime.

It is a D-number.

It is a Curzon number.

It is a plaindrome in base 16.

It is not an unprimeable number, because it can be changed into a prime (70849) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11799 + ... + 11804.

It is an arithmetic number, because the mean of its divisors is an integer number (23604).

2⁷⁰⁸⁰⁹ is an apocalyptic number.

It is an amenable number.

70809 is a deficient number, since it is larger than the sum of its proper divisors (23607).

70809 is a wasteful number, since it uses less digits than its factorization.

70809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23606.

The product of its (nonzero) digits is 504, while the sum is 24.

The square root of 70809 is about 266.0996054112. The cubic root of 70809 is about 41.3710128717.

The spelling of 70809 in words is "seventy thousand, eight hundred nine".