199556561966 has 4 divisors (see below), whose sum is σ = 299334842952. Its totient is φ = 99778280982.

The previous prime is 199556561951. The next prime is 199556561999. The reversal of 199556561966 is 669165655991.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 199556561896 and 199556561905.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49889140490 + ... + 49889140493.

It is an arithmetic number, because the mean of its divisors is an integer number (74833710738).

Almost surely, 2^199556561966 is an apocalyptic number.

199556561966 is a deficient number, since it is larger than the sum of its proper divisors (99778280986).

199556561966 is an equidigital number, since it uses as much as digits as its factorization.

199556561966 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 99778280985.

The product of its digits is 118098000, while the sum is 68.

The spelling of 199556561966 in words is "one hundred ninety-nine billion, five hundred fifty-six million, five hundred sixty-one thousand, nine hundred sixty-six".