198542427561 has 27 divisors (see below), whose sum is σ = 297852656023. Its totient is φ = 132337557000.

The previous prime is 198542427541. The next prime is 198542427563. The reversal of 198542427561 is 165724245891.

The square root of 198542427561 is 445581.

It is a perfect power (a square), and thus also a powerful number.

198542427561 is a `hidden beast` number, since 1 + 9 + 8 + 54 + 2 + 4 + 27 + 561 = 666.

It can be written as a sum of positive squares in only one way, i.e., 194949623961 + 3592803600 = 441531^2 + 59940^2 .

It is a tau number, because it is divible by the number of its divisors (27).

It is not a de Polignac number, because 198542427561 - 2¹⁵ = 198542394793 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 198542427498 and 198542427507.

It is not an unprimeable number, because it can be changed into a prime (198542427563) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 36089311 + ... + 36094811.

Almost surely, 2^198542427561 is an apocalyptic number.

198542427561 is the 445581-st square number.

198542427561 is the 222791-st centered octagonal number.

It is an amenable number.

198542427561 is a deficient number, since it is larger than the sum of its proper divisors (99310228462).

198542427561 is an frugal number, since it uses more digits than its factorization.

198542427561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11026 (or 5504 counting only the distinct ones).

The product of its digits is 4838400, while the sum is 54.

The spelling of 198542427561 in words is "one hundred ninety-eight billion, five hundred forty-two million, four hundred twenty-seven thousand, five hundred sixty-one".