999688643 has 2 divisors, whose sum is σ = 999688644. Its totient is φ = 999688642.

The previous prime is 999688633. The next prime is 999688649. The reversal of 999688643 is 346886999.

999688643 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 999688643 - 2⁸ = 999688387 is a prime.

It is not a weakly prime, because it can be changed into another prime (999688649) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499844321 + 499844322.

It is an arithmetic number, because the mean of its divisors is an integer number (499844322).

Almost surely, 2^999688643 is an apocalyptic number.

999688643 is a deficient number, since it is larger than the sum of its proper divisors (1).

999688643 is an equidigital number, since it uses as much as digits as its factorization.

999688643 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 20155392, while the sum is 62.

The square root of 999688643 is about 31617.8532319954. The cubic root of 999688643 is about 999.8962035600.

The spelling of 999688643 in words is "nine hundred ninety-nine million, six hundred eighty-eight thousand, six hundred forty-three".