9987521 has 8 divisors (see below), whose sum is σ = 10798080. Its totient is φ = 9205488.

The previous prime is 9987511. The next prime is 9987533. The reversal of 9987521 is 1257899.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 9987521 - 2⁶ = 9987457 is a prime.

It is a nialpdrome in base 10.

It is not an unprimeable number, because it can be changed into a prime (9987511) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6401 + ... + 7806.

It is an arithmetic number, because the mean of its divisors is an integer number (1349760).

Almost surely, 2^9987521 is an apocalyptic number.

It is an amenable number.

9987521 is a deficient number, since it is larger than the sum of its proper divisors (810559).

9987521 is a wasteful number, since it uses less digits than its factorization.

9987521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14263.

The product of its digits is 45360, while the sum is 41.

The square root of 9987521 is about 3160.3039410791. The cubic root of 9987521 is about 215.3538143979.

The spelling of 9987521 in words is "nine million, nine hundred eighty-seven thousand, five hundred twenty-one".