1999997807 has 2 divisors, whose sum is σ = 1999997808. Its totient is φ = 1999997806.

The previous prime is 1999997777. The next prime is 1999997849. The reversal of 1999997807 is 7087999991.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1999997807 - 2³⁰ = 926255983 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1999997887) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 999998903 + 999998904.

It is an arithmetic number, because the mean of its divisors is an integer number (999998904).

Almost surely, 2^1999997807 is an apocalyptic number.

1999997807 is a deficient number, since it is larger than the sum of its proper divisors (1).

1999997807 is an equidigital number, since it uses as much as digits as its factorization.

1999997807 is an evil number, because the sum of its binary digits is even.

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

The square root of 1999997807 is about 44721.3350315037. The cubic root of 1999997807 is about 1259.9205893936.

The spelling of 1999997807 in words is "one billion, nine hundred ninety-nine million, nine hundred ninety-seven thousand, eight hundred seven".