1999988797 has 2 divisors, whose sum is σ = 1999988798. Its totient is φ = 1999988796.

The previous prime is 1999988779. The next prime is 1999988803. The reversal of 1999988797 is 7978899991.

It is a happy number.

Together with previous prime (1999988779) 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., 1998894681 + 1094116 = 44709^2 + 1046^2 .

It is a cyclic number.

It is not a de Polignac number, because 1999988797 - 2²⁷ = 1865771069 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1999988717) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 999994398 + 999994399.

It is an arithmetic number, because the mean of its divisors is an integer number (999994399).

Almost surely, 2^1999988797 is an apocalyptic number.

It is an amenable number.

1999988797 is a deficient number, since it is larger than the sum of its proper divisors (1).

1999988797 is an equidigital number, since it uses as much as digits as its factorization.

1999988797 is an evil number, because the sum of its binary digits is even.

The product of its digits is 185177664, while the sum is 76.

The square root of 1999988797 is about 44721.2342964726. The cubic root of 1999988797 is about 1259.9186974079.

The spelling of 1999988797 in words is "one billion, nine hundred ninety-nine million, nine hundred eighty-eight thousand, seven hundred ninety-seven".