1999889 has 2 divisors, whose sum is σ = 1999890. Its totient is φ = 1999888.

The previous prime is 1999871. The next prime is 1999891. The reversal of 1999889 is 9889991.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1669264 + 330625 = 1292^2 + 575^2 .

It is a cyclic number.

It is not a de Polignac number, because 1999889 - 2⁸ = 1999633 is a prime.

Together with 1999891, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1999889.

It is not a weakly prime, because it can be changed into another prime (1999819) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 999944 + 999945.

It is an arithmetic number, because the mean of its divisors is an integer number (999945).

2^1999889 is an apocalyptic number.

It is an amenable number.

1999889 is a deficient number, since it is larger than the sum of its proper divisors (1).

1999889 is an equidigital number, since it uses as much as digits as its factorization.

1999889 is an evil number, because the sum of its binary digits is even.

The product of its digits is 419904, while the sum is 53.

The square root of 1999889 is about 1414.1743174022. The cubic root of 1999889 is about 125.9897740924.

The spelling of 1999889 in words is "one million, nine hundred ninety-nine thousand, eight hundred eighty-nine".