78678691 has 16 divisors (see below), whose sum is σ = 99092224. Its totient is φ = 60800544.

The previous prime is 78678679. The next prime is 78678763. The reversal of 78678691 is 19687687.

It is not a de Polignac number, because 78678691 - 2⁹ = 78678179 is a prime.

It is not an unprimeable number, because it can be changed into a prime (78676691) 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 15 ways as a sum of consecutive naturals, for example, 6141 + ... + 13966.

It is an arithmetic number, because the mean of its divisors is an integer number (6193264).

Almost surely, 2^78678691 is an apocalyptic number.

78678691 is a deficient number, since it is larger than the sum of its proper divisors (20413533).

78678691 is a wasteful number, since it uses less digits than its factorization.

78678691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20170.

The product of its digits is 1016064, while the sum is 52.

The square root of 78678691 is about 8870.1009577118. The cubic root of 78678691 is about 428.5015283512.

The spelling of 78678691 in words is "seventy-eight million, six hundred seventy-eight thousand, six hundred ninety-one".