999000000643 has 2 divisors, whose sum is σ = 999000000644. Its totient is φ = 999000000642.

The previous prime is 999000000617. The next prime is 999000000667. The reversal of 999000000643 is 346000000999.

It is a strong prime.

It is an emirp because it is prime and its reverse (346000000999) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 999000000643 - 2⁵ = 999000000611 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 999000000596 and 999000000605.

It is not a weakly prime, because it can be changed into another prime (999000000613) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499500000321 + 499500000322.

It is an arithmetic number, because the mean of its divisors is an integer number (499500000322).

Almost surely, 2^999000000643 is an apocalyptic number.

999000000643 is a deficient number, since it is larger than the sum of its proper divisors (1).

999000000643 is an equidigital number, since it uses as much as digits as its factorization.

999000000643 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 52488, while the sum is 40.

The spelling of 999000000643 in words is "nine hundred ninety-nine billion, six hundred forty-three", and thus it is an aban number.