78090909 has 8 divisors (see below), whose sum is σ = 112130592. Its totient is φ = 48055920.

The previous prime is 78090899. The next prime is 78090913. The reversal of 78090909 is 90909087.

It is a happy number.

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

It is not a de Polignac number, because 78090909 - 2¹⁷ = 77959837 is a prime.

78090909 is a modest number, since divided by 90909 gives 78 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78090949) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1001127 + ... + 1001204.

It is an arithmetic number, because the mean of its divisors is an integer number (14016324).

Almost surely, 2^78090909 is an apocalyptic number.

It is an amenable number.

78090909 is a deficient number, since it is larger than the sum of its proper divisors (34039683).

78090909 is a wasteful number, since it uses less digits than its factorization.

78090909 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2002347.

The product of its (nonzero) digits is 40824, while the sum is 42.

The square root of 78090909 is about 8836.9060762237. The cubic root of 78090909 is about 427.4317965131.

The spelling of 78090909 in words is "seventy-eight million, ninety thousand, nine hundred nine".