1999340789 has 2 divisors, whose sum is σ = 1999340790. Its totient is φ = 1999340788.

The previous prime is 1999340779. The next prime is 1999340897. The reversal of 1999340789 is 9870439991.

Together with next prime (1999340897) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1992104689 + 7236100 = 44633^2 + 2690^2 .

It is a cyclic number.

It is not a de Polignac number, because 1999340789 - 2²⁰ = 1998292213 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1999340719) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 999670394 + 999670395.

It is an arithmetic number, because the mean of its divisors is an integer number (999670395).

Almost surely, 2^1999340789 is an apocalyptic number.

It is an amenable number.

1999340789 is a deficient number, since it is larger than the sum of its proper divisors (1).

1999340789 is an equidigital number, since it uses as much as digits as its factorization.

1999340789 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4408992, while the sum is 59.

The square root of 1999340789 is about 44713.9887395432. The cubic root of 1999340789 is about 1259.7826090476.

The spelling of 1999340789 in words is "one billion, nine hundred ninety-nine million, three hundred forty thousand, seven hundred eighty-nine".