9891540 has 72 divisors (see below), whose sum is σ = 30270240. Its totient is φ = 2614464.

The previous prime is 9891517. The next prime is 9891551. The reversal of 9891540 is 451989.

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

It is an Ulam number.

It is a junction number, because it is equal to n+sod(n) for n = 9891495 and 9891504.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 32067 + ... + 32373.

It is an arithmetic number, because the mean of its divisors is an integer number (420420).

Almost surely, 2^9891540 is an apocalyptic number.

9891540 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 9891540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (15135120).

9891540 is an abundant number, since it is smaller than the sum of its proper divisors (20378700).

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

9891540 is a wasteful number, since it uses less digits than its factorization.

9891540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 501 (or 496 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 36.

The square root of 9891540 is about 3145.0818749279. The cubic root of 9891540 is about 214.6617359737.

The spelling of 9891540 in words is "nine million, eight hundred ninety-one thousand, five hundred forty".