9981621 has 12 divisors (see below), whose sum is σ = 15527148. Its totient is φ = 6142464.

The previous prime is 9981611. The next prime is 9981637. The reversal of 9981621 is 1261899.

9981621 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 6687396 + 3294225 = 2586^2 + 1815^2 .

It is not a de Polignac number, because 9981621 - 2⁶ = 9981557 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9981611) 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, 42540 + ... + 42773.

It is an arithmetic number, because the mean of its divisors is an integer number (1293929).

Almost surely, 2^9981621 is an apocalyptic number.

It is an amenable number.

9981621 is a deficient number, since it is larger than the sum of its proper divisors (5545527).

9981621 is a wasteful number, since it uses less digits than its factorization.

9981621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 85332 (or 85329 counting only the distinct ones).

The product of its digits is 7776, while the sum is 36.

The square root of 9981621 is about 3159.3703486613. The cubic root of 9981621 is about 215.3114002098.

The spelling of 9981621 in words is "nine million, nine hundred eighty-one thousand, six hundred twenty-one".