9981720 has 192 divisors, whose sum is σ = 39424320. Its totient is φ = 2138112.

The previous prime is 9981691. The next prime is 9981731. The reversal of 9981720 is 271899.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 42724 + ... + 42956.

It is an arithmetic number, because the mean of its divisors is an integer number (205335).

Almost surely, 2^9981720 is an apocalyptic number.

9981720 is a gapful number since it is divisible by the number (90) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 9981720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (19712160).

9981720 is an abundant number, since it is smaller than the sum of its proper divisors (29442600).

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

9981720 is a wasteful number, since it uses less digits than its factorization.

9981720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 274 (or 267 counting only the distinct ones).

The product of its (nonzero) digits is 9072, while the sum is 36.

The square root of 9981720 is about 3159.3860163013. The cubic root of 9981720 is about 215.3121120434.

It can be divided in two parts, 9981 and 720, that added together give a palindrome (10701).

The spelling of 9981720 in words is "nine million, nine hundred eighty-one thousand, seven hundred twenty".