91666647 has 14 divisors (see below), whose sum is σ = 137438192. Its totient is φ = 61110612.

The previous prime is 91666633. The next prime is 91666667. The reversal of 91666647 is 74666619.

It is a happy number.

It is not a de Polignac number, because 91666647 - 2¹² = 91662551 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91666607) 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 13 ways as a sum of consecutive naturals, for example, 62143 + ... + 63600.

Almost surely, 2^91666647 is an apocalyptic number.

91666647 is a deficient number, since it is larger than the sum of its proper divisors (45771545).

91666647 is an equidigital number, since it uses as much as digits as its factorization.

91666647 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 125761 (or 125746 counting only the distinct ones).

The product of its digits is 326592, while the sum is 45.

The square root of 91666647 is about 9574.2700505052. The cubic root of 91666647 is about 450.8898392537.

The spelling of 91666647 in words is "ninety-one million, six hundred sixty-six thousand, six hundred forty-seven".