1999987097 has 2 divisors, whose sum is σ = 1999987098. Its totient is φ = 1999987096.

The previous prime is 1999987079. The next prime is 1999987109. The reversal of 1999987097 is 7907899991.

Together with previous prime (1999987079) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1100646976 + 899340121 = 33176^2 + 29989^2 .

It is a cyclic number.

It is not a de Polignac number, because 1999987097 - 2²⁴ = 1983209881 is a prime.

It is not a weakly prime, because it can be changed into another prime (1999989097) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 999993548 + 999993549.

It is an arithmetic number, because the mean of its divisors is an integer number (999993549).

Almost surely, 2^1999987097 is an apocalyptic number.

It is an amenable number.

1999987097 is a deficient number, since it is larger than the sum of its proper divisors (1).

1999987097 is an equidigital number, since it uses as much as digits as its factorization.

1999987097 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 23147208, while the sum is 68.

The square root of 1999987097 is about 44721.2152898376. The cubic root of 1999987097 is about 1259.9183404288.

The spelling of 1999987097 in words is "one billion, nine hundred ninety-nine million, nine hundred eighty-seven thousand, ninety-seven".