9987581 has 4 divisors (see below), whose sum is σ = 10040064. Its totient is φ = 9935100.

The previous prime is 9987577. The next prime is 9987617. The reversal of 9987581 is 1857899.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 9987581 - 2² = 9987577 is a prime.

It is a super-2 number, since 2×9987581² = 199503548463122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

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 3 ways as a sum of consecutive naturals, for example, 25955 + ... + 26336.

It is an arithmetic number, because the mean of its divisors is an integer number (2510016).

Almost surely, 2^9987581 is an apocalyptic number.

It is an amenable number.

9987581 is a deficient number, since it is larger than the sum of its proper divisors (52483).

9987581 is a wasteful number, since it uses less digits than its factorization.

9987581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52482.

The product of its digits is 181440, while the sum is 47.

The square root of 9987581 is about 3160.3134338227. The cubic root of 9987581 is about 215.3542456428.

The spelling of 9987581 in words is "nine million, nine hundred eighty-seven thousand, five hundred eighty-one".