9999643 has 4 divisors (see below), whose sum is σ = 10525960. Its totient is φ = 9473328.

The previous prime is 9999637. The next prime is 9999653. The reversal of 9999643 is 3469999.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 9999643 - 2¹³ = 9991451 is a prime.

It is a Duffinian number.

9999643 is a lucky number.

It is a nialpdrome in base 10.

It is not an unprimeable number, because it can be changed into a prime (9999653) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 263130 + ... + 263167.

It is an arithmetic number, because the mean of its divisors is an integer number (2631490).

Almost surely, 2^9999643 is an apocalyptic number.

9999643 is a deficient number, since it is larger than the sum of its proper divisors (526317).

9999643 is a wasteful number, since it uses less digits than its factorization.

9999643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 526316.

The product of its digits is 472392, while the sum is 49.

The square root of 9999643 is about 3162.2212130083. The cubic root of 9999643 is about 215.4409051954.

The spelling of 9999643 in words is "nine million, nine hundred ninety-nine thousand, six hundred forty-three".