9966391 has 4 divisors (see below), whose sum is σ = 10086552. Its totient is φ = 9846232.

The previous prime is 9966389. The next prime is 9966409. The reversal of 9966391 is 1936699.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1936699 = 167 ⋅11597.

It is a cyclic number.

It is not a de Polignac number, because 9966391 - 2¹ = 9966389 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 (9966331) 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 3 ways as a sum of consecutive naturals, for example, 59956 + ... + 60121.

It is an arithmetic number, because the mean of its divisors is an integer number (2521638).

Almost surely, 2^9966391 is an apocalyptic number.

9966391 is a deficient number, since it is larger than the sum of its proper divisors (120161).

9966391 is a wasteful number, since it uses less digits than its factorization.

9966391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 120160.

The product of its digits is 78732, while the sum is 43.

The square root of 9966391 is about 3156.9591381581. The cubic root of 9966391 is about 215.2018367818.

The spelling of 9966391 in words is "nine million, nine hundred sixty-six thousand, three hundred ninety-one".