78775909 has 6 divisors (see below), whose sum is σ = 83682674. Its totient is φ = 74141760.

The previous prime is 78775903. The next prime is 78775913. The reversal of 78775909 is 90957787.

It can be written as a sum of positive squares in 3 ways, for example, as 37173409 + 41602500 = 6097^2 + 6450^2 .

It is not a de Polignac number, because 78775909 - 2²³ = 70387301 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 (78775903) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 136002 + ... + 136579.

Almost surely, 2^78775909 is an apocalyptic number.

It is an amenable number.

78775909 is a deficient number, since it is larger than the sum of its proper divisors (4906765).

78775909 is a wasteful number, since it uses less digits than its factorization.

78775909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 272615 (or 272598 counting only the distinct ones).

The product of its (nonzero) digits is 1111320, while the sum is 52.

The square root of 78775909 is about 8875.5793613713. The cubic root of 78775909 is about 428.6779459419.

The spelling of 78775909 in words is "seventy-eight million, seven hundred seventy-five thousand, nine hundred nine".