9966640 has 80 divisors (see below), whose sum is σ = 24998400. Its totient is φ = 3684096.

The previous prime is 9966629. The next prime is 9966643. The reversal of 9966640 is 466699.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a nialpdrome in base 10.

It is a junction number, because it is equal to n+sod(n) for n = 9966593 and 9966602.

It is not an unprimeable number, because it can be changed into a prime (9966643) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 120039 + ... + 120121.

It is an arithmetic number, because the mean of its divisors is an integer number (312480).

Almost surely, 2^9966640 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 9966640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (12499200).

9966640 is an abundant number, since it is smaller than the sum of its proper divisors (15031760).

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

9966640 is a wasteful number, since it uses less digits than its factorization.

9966640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 194 (or 188 counting only the distinct ones).

The product of its (nonzero) digits is 69984, while the sum is 40.

The square root of 9966640 is about 3156.9985745958. The cubic root of 9966640 is about 215.2036289655.

The spelling of 9966640 in words is "nine million, nine hundred sixty-six thousand, six hundred forty".