9987621 has 12 divisors (see below), whose sum is σ = 15491232. Its totient is φ = 5707128.

The previous prime is 9987617. The next prime is 9987643. The reversal of 9987621 is 1267899.

It is not a de Polignac number, because 9987621 - 2² = 9987617 is a prime.

It is a nialpdrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9987671) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 33825 + ... + 34118.

It is an arithmetic number, because the mean of its divisors is an integer number (1290936).

Almost surely, 2^9987621 is an apocalyptic number.

It is an amenable number.

9987621 is a deficient number, since it is larger than the sum of its proper divisors (5503611).

9987621 is a wasteful number, since it uses less digits than its factorization.

9987621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 67960 (or 67953 counting only the distinct ones).

The product of its digits is 54432, while the sum is 42.

The square root of 9987621 is about 3160.3197623025. The cubic root of 9987621 is about 215.3545331384.

The spelling of 9987621 in words is "nine million, nine hundred eighty-seven thousand, six hundred twenty-one".