9843981621 has 4 divisors (see below), whose sum is σ = 13125308832. Its totient is φ = 6562654412.

The previous prime is 9843981607. The next prime is 9843981629. The reversal of 9843981621 is 1261893489.

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, and also an emirpimes, since its reverse is a distinct semiprime: 1261893489 = 3 ⋅420631163.

It is a cyclic number.

It is not a de Polignac number, because 9843981621 - 2⁶ = 9843981557 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9843981629) 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, 1640663601 + ... + 1640663606.

It is an arithmetic number, because the mean of its divisors is an integer number (3281327208).

Almost surely, 2^9843981621 is an apocalyptic number.

It is an amenable number.

9843981621 is a deficient number, since it is larger than the sum of its proper divisors (3281327211).

9843981621 is a wasteful number, since it uses less digits than its factorization.

9843981621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3281327210.

The product of its digits is 746496, while the sum is 51.

The square root of 9843981621 is about 99216.8414181786. The cubic root of 9843981621 is about 2143.1715297465.

The spelling of 9843981621 in words is "nine billion, eight hundred forty-three million, nine hundred eighty-one thousand, six hundred twenty-one".