91678786 has 4 divisors (see below), whose sum is σ = 137518182. Its totient is φ = 45839392.

The previous prime is 91678771. The next prime is 91678787. The reversal of 91678786 is 68787619.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 68787619 = 19 ⋅3620401.

It can be written as a sum of positive squares in only one way, i.e., 87778161 + 3900625 = 9369^2 + 1975^2 .

It is not an unprimeable number, because it can be changed into a prime (91678787) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 22919695 + ... + 22919698.

Almost surely, 2^91678786 is an apocalyptic number.

91678786 is a deficient number, since it is larger than the sum of its proper divisors (45839396).

91678786 is a wasteful number, since it uses less digits than its factorization.

91678786 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45839395.

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

The square root of 91678786 is about 9574.9039681868. The cubic root of 91678786 is about 450.9097414768.

The spelling of 91678786 in words is "ninety-one million, six hundred seventy-eight thousand, seven hundred eighty-six".