78135809 has 8 divisors (see below), whose sum is σ = 82499040. Its totient is φ = 73797696.

The previous prime is 78135803. The next prime is 78135821. The reversal of 78135809 is 90853187.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 78135809 - 2²⁰ = 77087233 is a prime.

It is a super-2 number, since 2×78135809² = 12210409296168962, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78135803) 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 7 ways as a sum of consecutive naturals, for example, 302 + ... + 12504.

It is an arithmetic number, because the mean of its divisors is an integer number (10312380).

Almost surely, 2^78135809 is an apocalyptic number.

It is an amenable number.

78135809 is a deficient number, since it is larger than the sum of its proper divisors (4363231).

78135809 is a wasteful number, since it uses less digits than its factorization.

78135809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12559.

The product of its (nonzero) digits is 60480, while the sum is 41.

The square root of 78135809 is about 8839.4461930598. The cubic root of 78135809 is about 427.5137010987.

The spelling of 78135809 in words is "seventy-eight million, one hundred thirty-five thousand, eight hundred nine".