199801999777 has 2 divisors, whose sum is σ = 199801999778. Its totient is φ = 199801999776.

The previous prime is 199801999757. The next prime is 199801999841. The reversal of 199801999777 is 777999108991.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 165330878881 + 34471120896 = 406609^2 + 185664^2 .

It is a cyclic number.

It is not a de Polignac number, because 199801999777 - 2¹¹ = 199801997729 is a prime.

It is a super-2 number, since 2×199801999777² (a number of 23 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (199801999717) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 99900999888 + 99900999889.

It is an arithmetic number, because the mean of its divisors is an integer number (99900999889).

Almost surely, 2^199801999777 is an apocalyptic number.

It is an amenable number.

199801999777 is a deficient number, since it is larger than the sum of its proper divisors (1).

199801999777 is an equidigital number, since it uses as much as digits as its factorization.

199801999777 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 162030456, while the sum is 76.

The spelling of 199801999777 in words is "one hundred ninety-nine billion, eight hundred one million, nine hundred ninety-nine thousand, seven hundred seventy-seven".