78306685 has 4 divisors (see below), whose sum is σ = 93968028. Its totient is φ = 62645344.

The previous prime is 78306659. The next prime is 78306703. The reversal of 78306685 is 58660387.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 58660387 = 17 ⋅3450611.

It can be written as a sum of positive squares in 2 ways, for example, as 43943641 + 34363044 = 6629^2 + 5862^2 .

It is a cyclic number.

It is not a de Polignac number, because 78306685 - 2¹⁵ = 78273917 is a prime.

It is a super-2 number, since 2×78306685² = 12263873831378450, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

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, 7830664 + ... + 7830673.

It is an arithmetic number, because the mean of its divisors is an integer number (23492007).

Almost surely, 2^78306685 is an apocalyptic number.

It is an amenable number.

78306685 is a deficient number, since it is larger than the sum of its proper divisors (15661343).

78306685 is a wasteful number, since it uses less digits than its factorization.

78306685 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15661342.

The product of its (nonzero) digits is 241920, while the sum is 43.

The square root of 78306685 is about 8849.1064520662. The cubic root of 78306685 is about 427.8251188900.

The spelling of 78306685 in words is "seventy-eight million, three hundred six thousand, six hundred eighty-five".