1999428889 has 2 divisors, whose sum is σ = 1999428890. Its totient is φ = 1999428888.

The previous prime is 1999428853. The next prime is 1999428911. The reversal of 1999428889 is 9888249991.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1745568400 + 253860489 = 41780^2 + 15933^2 .

It is a cyclic number.

It is not a de Polignac number, because 1999428889 - 2¹¹ = 1999426841 is a prime.

It is not a weakly prime, because it can be changed into another prime (1999428589) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 999714444 + 999714445.

It is an arithmetic number, because the mean of its divisors is an integer number (999714445).

Almost surely, 2^1999428889 is an apocalyptic number.

It is an amenable number.

1999428889 is a deficient number, since it is larger than the sum of its proper divisors (1).

1999428889 is an equidigital number, since it uses as much as digits as its factorization.

1999428889 is an evil number, because the sum of its binary digits is even.

The product of its digits is 26873856, while the sum is 67.

The square root of 1999428889 is about 44714.9738790039. The cubic root of 1999428889 is about 1259.8011126828.

The spelling of 1999428889 in words is "one billion, nine hundred ninety-nine million, four hundred twenty-eight thousand, eight hundred eighty-nine".