199556655991 has 16 divisors (see below), whose sum is σ = 263433081600. Its totient is φ = 146351710080.

The previous prime is 199556655989. The next prime is 199556656001.

199556655991 is nontrivially palindromic in base 10.

It is a cyclic number.

It is not a de Polignac number, because 199556655991 - 2¹ = 199556655989 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 199556655991.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (199556655491) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 76223541 + ... + 76226158.

It is an arithmetic number, because the mean of its divisors is an integer number (16464567600).

Almost surely, 2^199556655991 is an apocalyptic number.

199556655991 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

199556655991 is a deficient number, since it is larger than the sum of its proper divisors (63876425609).

199556655991 is a wasteful number, since it uses less digits than its factorization.

199556655991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 152449734.

The product of its digits is 147622500, while the sum is 70.

The spelling of 199556655991 in words is "one hundred ninety-nine billion, five hundred fifty-six million, six hundred fifty-five thousand, nine hundred ninety-one".