78109613 has 4 divisors (see below), whose sum is σ = 78263580. Its totient is φ = 77955648.

The previous prime is 78109601. The next prime is 78109621. The reversal of 78109613 is 31690187.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 71944324 + 6165289 = 8482^2 + 2483^2 .

It is a cyclic number.

It is not a de Polignac number, because 78109613 - 2²⁰ = 77061037 is a prime.

It is a super-2 number, since 2×78109613² = 12202223286019538, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78109813) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 76220 + ... + 77237.

It is an arithmetic number, because the mean of its divisors is an integer number (19565895).

Almost surely, 2^78109613 is an apocalyptic number.

It is an amenable number.

78109613 is a deficient number, since it is larger than the sum of its proper divisors (153967).

78109613 is a wasteful number, since it uses less digits than its factorization.

78109613 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 153966.

The product of its (nonzero) digits is 9072, while the sum is 35.

The square root of 78109613 is about 8837.9643018062. The cubic root of 78109613 is about 427.4659193332.

The spelling of 78109613 in words is "seventy-eight million, one hundred nine thousand, six hundred thirteen".