9921643 has 4 divisors (see below), whose sum is σ = 10241728. Its totient is φ = 9601560.

The previous prime is 9921641. The next prime is 9921679. The reversal of 9921643 is 3461299.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 3461299 = 89 ⋅38891.

It is a cyclic number.

It is not a de Polignac number, because 9921643 - 2¹ = 9921641 is a prime.

It is a Duffinian number.

9921643 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 9921599 and 9921608.

It is not an unprimeable number, because it can be changed into a prime (9921641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 159996 + ... + 160057.

It is an arithmetic number, because the mean of its divisors is an integer number (2560432).

Almost surely, 2^9921643 is an apocalyptic number.

9921643 is a deficient number, since it is larger than the sum of its proper divisors (320085).

9921643 is a wasteful number, since it uses less digits than its factorization.

9921643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 320084.

The product of its digits is 11664, while the sum is 34.

The square root of 9921643 is about 3149.8639653166. The cubic root of 9921643 is about 214.8792760148.

The spelling of 9921643 in words is "nine million, nine hundred twenty-one thousand, six hundred forty-three".