78940109 has 4 divisors (see below), whose sum is σ = 79353600. Its totient is φ = 78526620.

The previous prime is 78940097. The next prime is 78940133. The reversal of 78940109 is 90104987.

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: 90104987 = 7 ⋅12872141.

It is a cyclic number.

It is not a de Polignac number, because 78940109 - 2⁴ = 78940093 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 (78940139) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 206459 + ... + 206840.

It is an arithmetic number, because the mean of its divisors is an integer number (19838400).

Almost surely, 2^78940109 is an apocalyptic number.

It is an amenable number.

78940109 is a deficient number, since it is larger than the sum of its proper divisors (413491).

78940109 is a wasteful number, since it uses less digits than its factorization.

78940109 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 413490.

The product of its (nonzero) digits is 18144, while the sum is 38.

The square root of 78940109 is about 8884.8246465532. The cubic root of 78940109 is about 428.9755837608.

The spelling of 78940109 in words is "seventy-eight million, nine hundred forty thousand, one hundred nine".