1999765897 has 2 divisors, whose sum is σ = 1999765898. Its totient is φ = 1999765896.

The previous prime is 1999765861. The next prime is 1999765919. The reversal of 1999765897 is 7985679991.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1250046736 + 749719161 = 35356^2 + 27381^2 .

It is an emirp because it is prime and its reverse (7985679991) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1999765897 - 2⁷ = 1999765769 is a prime.

It is not a weakly prime, because it can be changed into another prime (1999765837) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 999882948 + 999882949.

It is an arithmetic number, because the mean of its divisors is an integer number (999882949).

Almost surely, 2^1999765897 is an apocalyptic number.

It is an amenable number.

1999765897 is a deficient number, since it is larger than the sum of its proper divisors (1).

1999765897 is an equidigital number, since it uses as much as digits as its factorization.

1999765897 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 77157360, while the sum is 70.

The square root of 1999765897 is about 44718.7421222914. The cubic root of 1999765897 is about 1259.8718894271.

The spelling of 1999765897 in words is "one billion, nine hundred ninety-nine million, seven hundred sixty-five thousand, eight hundred ninety-seven".