999989857 has 2 divisors, whose sum is σ = 999989858. Its totient is φ = 999989856.

The previous prime is 999989801. The next prime is 999989863. The reversal of 999989857 is 758989999.

999989857 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 can be written as a sum of positive squares in only one way, i.e., 862068321 + 137921536 = 29361^2 + 11744^2 .

It is a cyclic number.

It is not a de Polignac number, because 999989857 - 2²⁷ = 865772129 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 999989857.

It is not a weakly prime, because it can be changed into another prime (999989257) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499994928 + 499994929.

It is an arithmetic number, because the mean of its divisors is an integer number (499994929).

Almost surely, 2^999989857 is an apocalyptic number.

It is an amenable number.

999989857 is a deficient number, since it is larger than the sum of its proper divisors (1).

999989857 is an equidigital number, since it uses as much as digits as its factorization.

999989857 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 132269760, while the sum is 73.

The square root of 999989857 is about 31622.6162263656. The cubic root of 999989857 is about 999.9966189886.

It can be divided in two parts, 9999 and 89857, that added together give a square (99856 = 316²).

The spelling of 999989857 in words is "nine hundred ninety-nine million, nine hundred eighty-nine thousand, eight hundred fifty-seven".