199561 has 4 divisors (see below), whose sum is σ = 200772. Its totient is φ = 198352.

The previous prime is 199559. The next prime is 199567. The reversal of 199561 is 165991.

199561 is nontrivially palindromic in base 14.

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

It can be written as a sum of positive squares in 2 ways, for example, as 90000 + 109561 = 300^2 + 331^2 .

It is a cyclic number.

It is not a de Polignac number, because 199561 - 2¹ = 199559 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (199567) 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, 310 + ... + 703.

It is an arithmetic number, because the mean of its divisors is an integer number (50193).

2¹⁹⁹⁵⁶¹ is an apocalyptic number.

It is an amenable number.

199561 is a deficient number, since it is larger than the sum of its proper divisors (1211).

199561 is a wasteful number, since it uses less digits than its factorization.

199561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1210.

The product of its digits is 2430, while the sum is 31.

The square root of 199561 is about 446.7225089471. The cubic root of 199561 is about 58.4375352931.

The spelling of 199561 in words is "one hundred ninety-nine thousand, five hundred sixty-one".