78378617 has 8 divisors (see below), whose sum is σ = 80913096. Its totient is φ = 75866112.

The previous prime is 78378613. The next prime is 78378623. The reversal of 78378617 is 71687387.

It can be written as a sum of positive squares in 4 ways, for example, as 69039481 + 9339136 = 8309^2 + 3056^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 78378617 - 2² = 78378613 is a prime.

It is a super-3 number, since 3×78378617³ (a number of 25 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78378613) 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 7 ways as a sum of consecutive naturals, for example, 1913 + ... + 12665.

It is an arithmetic number, because the mean of its divisors is an integer number (10114137).

Almost surely, 2^78378617 is an apocalyptic number.

It is an amenable number.

78378617 is a deficient number, since it is larger than the sum of its proper divisors (2534479).

78378617 is a wasteful number, since it uses less digits than its factorization.

78378617 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10987.

The product of its digits is 395136, while the sum is 47.

The square root of 78378617 is about 8853.1698842844. The cubic root of 78378617 is about 427.9560779017.

The spelling of 78378617 in words is "seventy-eight million, three hundred seventy-eight thousand, six hundred seventeen".