999996643 has 2 divisors, whose sum is σ = 999996644. Its totient is φ = 999996642.

The previous prime is 999996611. The next prime is 999996649. The reversal of 999996643 is 346699999.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 999996643 - 2⁵ = 999996611 is a prime.

It is a super-2 number, since 2×999996643² = 1999986572022538898, which contains 22 as substring.

It is a nialpdrome in base 10.

It is not a weakly prime, because it can be changed into another prime (999996649) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499998321 + 499998322.

It is an arithmetic number, because the mean of its divisors is an integer number (499998322).

Almost surely, 2^999996643 is an apocalyptic number.

999996643 is a deficient number, since it is larger than the sum of its proper divisors (1).

999996643 is an equidigital number, since it uses as much as digits as its factorization.

999996643 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 25509168, while the sum is 64.

The square root of 999996643 is about 31622.7235228087. The cubic root of 999996643 is about 999.9988809987.

The spelling of 999996643 in words is "nine hundred ninety-nine million, nine hundred ninety-six thousand, six hundred forty-three".