199969789 has 2 divisors, whose sum is σ = 199969790. Its totient is φ = 199969788.

The previous prime is 199969787. The next prime is 199969817. The reversal of 199969789 is 987969991.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 198387225 + 1582564 = 14085^2 + 1258^2 .

It is a cyclic number.

It is not a de Polignac number, because 199969789 - 2¹ = 199969787 is a prime.

Together with 199969787, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (199969787) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99984894 + 99984895.

It is an arithmetic number, because the mean of its divisors is an integer number (99984895).

Almost surely, 2^199969789 is an apocalyptic number.

It is an amenable number.

199969789 is a deficient number, since it is larger than the sum of its proper divisors (1).

199969789 is an equidigital number, since it uses as much as digits as its factorization.

199969789 is an evil number, because the sum of its binary digits is even.

The product of its digits is 19840464, while the sum is 67.

The square root of 199969789 is about 14141.0674632434. The cubic root of 199969789 is about 584.7741003265.

The spelling of 199969789 in words is "one hundred ninety-nine million, nine hundred sixty-nine thousand, seven hundred eighty-nine".