78944909 has 4 divisors (see below), whose sum is σ = 79035804. Its totient is φ = 78854016.

The previous prime is 78944903. The next prime is 78944927. The reversal of 78944909 is 90944987.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 90944987 = 7 ⋅12992141.

It can be written as a sum of positive squares in 2 ways, for example, as 68724100 + 10220809 = 8290^2 + 3197^2 .

It is a cyclic number.

It is not a de Polignac number, because 78944909 - 2⁴ = 78944893 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78944903) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 44132 + ... + 45885.

It is an arithmetic number, because the mean of its divisors is an integer number (19758951).

Almost surely, 2^78944909 is an apocalyptic number.

It is an amenable number.

78944909 is a deficient number, since it is larger than the sum of its proper divisors (90895).

78944909 is an equidigital number, since it uses as much as digits as its factorization.

78944909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 90894.

The product of its (nonzero) digits is 653184, while the sum is 50.

The square root of 78944909 is about 8885.0947659549. The cubic root of 78944909 is about 428.9842782892.

The spelling of 78944909 in words is "seventy-eight million, nine hundred forty-four thousand, nine hundred nine".