999863989 has 2 divisors, whose sum is σ = 999863990. Its totient is φ = 999863988.

The previous prime is 999863983. The next prime is 999864017. The reversal of 999863989 is 989368999.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 695640625 + 304223364 = 26375^2 + 17442^2 .

It is a cyclic number.

It is not a de Polignac number, because 999863989 - 2⁷ = 999863861 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (999863983) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499931994 + 499931995.

It is an arithmetic number, because the mean of its divisors is an integer number (499931995).

Almost surely, 2^999863989 is an apocalyptic number.

It is an amenable number.

999863989 is a deficient number, since it is larger than the sum of its proper divisors (1).

999863989 is an equidigital number, since it uses as much as digits as its factorization.

999863989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 68024448, while the sum is 70.

The square root of 999863989 is about 31620.6260058209. The cubic root of 999863989 is about 999.9546609444.

The spelling of 999863989 in words is "nine hundred ninety-nine million, eight hundred sixty-three thousand, nine hundred eighty-nine".