9978640 has 80 divisors (see below), whose sum is σ = 26926848. Its totient is φ = 3368448.

The previous prime is 9978637. The next prime is 9978649. The reversal of 9978640 is 468799.

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

It is a nialpdrome in base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9978649) 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, 57594 + ... + 57766.

Almost surely, 2^9978640 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 9978640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (13463424).

9978640 is an abundant number, since it is smaller than the sum of its proper divisors (16948208).

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

9978640 is a wasteful number, since it uses less digits than its factorization.

9978640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 296 (or 290 counting only the distinct ones).

The product of its (nonzero) digits is 108864, while the sum is 43.

The square root of 9978640 is about 3158.8985422137. The cubic root of 9978640 is about 215.2899639057.

The spelling of 9978640 in words is "nine million, nine hundred seventy-eight thousand, six hundred forty".