9979640 has 64 divisors (see below), whose sum is σ = 25198560. Its totient is φ = 3525120.

The previous prime is 9979639. The next prime is 9979643. The reversal of 9979640 is 469799.

It is a Harshad number since it is a multiple of its sum of digits (44).

It is a junction number, because it is equal to n+sod(n) for n = 9979591 and 9979600.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9979643) 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 15 ways as a sum of consecutive naturals, for example, 15974 + ... + 16586.

Almost surely, 2^9979640 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 9979640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (12599280).

9979640 is an abundant number, since it is smaller than the sum of its proper divisors (15218920).

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

9979640 is a wasteful number, since it uses less digits than its factorization.

9979640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 672 (or 668 counting only the distinct ones).

The product of its (nonzero) digits is 122472, while the sum is 44.

The square root of 9979640 is about 3159.0568212680. The cubic root of 9979640 is about 215.2971553591.

The spelling of 9979640 in words is "nine million, nine hundred seventy-nine thousand, six hundred forty".