197661 has 8 divisors (see below), whose sum is σ = 270144. Its totient is φ = 128480.

The previous prime is 197651. The next prime is 197677. The reversal of 197661 is 166791.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 197661 - 2⁶ = 197597 is a prime.

It is an Ulam number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (197621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 681 + ... + 926.

It is an arithmetic number, because the mean of its divisors is an integer number (33768).

2¹⁹⁷⁶⁶¹ is an apocalyptic number.

It is an amenable number.

197661 is a deficient number, since it is larger than the sum of its proper divisors (72483).

197661 is a wasteful number, since it uses less digits than its factorization.

197661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1651.

The product of its digits is 2268, while the sum is 30.

The square root of 197661 is about 444.5908231172. The cubic root of 197661 is about 58.2514843022.

It can be divided in two parts, 197 and 661, that added together give a palindrome (858).

The spelling of 197661 in words is "one hundred ninety-seven thousand, six hundred sixty-one".