199979993881 has 4 divisors (see below), whose sum is σ = 199980913972. Its totient is φ = 199979073792.

The previous prime is 199979993869. The next prime is 199979993891. The reversal of 199979993881 is 188399979991.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 188399979991 = 83 ⋅2269879277.

It can be written as a sum of positive squares in 2 ways, for example, as 111285624025 + 88694369856 = 333595^2 + 297816^2 .

It is a cyclic number.

It is not a de Polignac number, because 199979993881 - 2²⁵ = 199946439449 is a prime.

It is a super-2 number, since 2×199979993881² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 199979993795 and 199979993804.

It is not an unprimeable number, because it can be changed into a prime (199979993861) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 68041 + ... + 636073.

It is an arithmetic number, because the mean of its divisors is an integer number (49995228493).

Almost surely, 2^199979993881 is an apocalyptic number.

It is an amenable number.

199979993881 is a deficient number, since it is larger than the sum of its proper divisors (920091).

199979993881 is an equidigital number, since it uses as much as digits as its factorization.

199979993881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 920090.

The product of its digits is 714256704, while the sum is 82.

The spelling of 199979993881 in words is "one hundred ninety-nine billion, nine hundred seventy-nine million, nine hundred ninety-three thousand, eight hundred eighty-one".