198188261 has 4 divisors (see below), whose sum is σ = 209846412. Its totient is φ = 186530112.

The previous prime is 198188251. The next prime is 198188273. The reversal of 198188261 is 162881891.

198188261 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 170824900 + 27363361 = 13070^2 + 5231^2 .

It is a cyclic number.

It is not a de Polignac number, because 198188261 - 2¹⁸ = 197926117 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 (198188231) 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, 5829050 + ... + 5829083.

It is an arithmetic number, because the mean of its divisors is an integer number (52461603).

Almost surely, 2^198188261 is an apocalyptic number.

It is an amenable number.

198188261 is a deficient number, since it is larger than the sum of its proper divisors (11658151).

198188261 is a wasteful number, since it uses less digits than its factorization.

198188261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11658150.

The product of its digits is 55296, while the sum is 44.

The square root of 198188261 is about 14077.9352534383. The cubic root of 198188261 is about 583.0323362148.

The spelling of 198188261 in words is "one hundred ninety-eight million, one hundred eighty-eight thousand, two hundred sixty-one".