9987840 has 216 divisors, whose sum is σ = 37650480. Its totient is φ = 2506752.

The previous prime is 9987827. The next prime is 9987841. The reversal of 9987840 is 487899.

It is a tau number, because it is divible by the number of its divisors (216).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9987841) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 587512 + ... + 587528.

Almost surely, 2^9987840 is an apocalyptic number.

9987840 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 9987840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (18825240).

9987840 is an abundant number, since it is smaller than the sum of its proper divisors (27662640).

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

9987840 is a wasteful number, since it uses less digits than its factorization.

9987840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64 (or 27 counting only the distinct ones).

The product of its (nonzero) digits is 145152, while the sum is 45.

The square root of 9987840 is about 3160.3544105053. The cubic root of 9987840 is about 215.3561071635.

The spelling of 9987840 in words is "nine million, nine hundred eighty-seven thousand, eight hundred forty".