9991686 has 16 divisors (see below), whose sum is σ = 20161584. Its totient is φ = 3300864.

The previous prime is 9991673. The next prime is 9991691. The reversal of 9991686 is 6861999.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6691 + ... + 8046.

It is an arithmetic number, because the mean of its divisors is an integer number (1260099).

Almost surely, 2^9991686 is an apocalyptic number.

9991686 is an abundant number, since it is smaller than the sum of its proper divisors (10169898).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

9991686 is a wasteful number, since it uses less digits than its factorization.

9991686 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14855.

The product of its digits is 209952, while the sum is 48.

The square root of 9991686 is about 3160.9628280004. The cubic root of 9991686 is about 215.3837458822.

The spelling of 9991686 in words is "nine million, nine hundred ninety-one thousand, six hundred eighty-six".