189661 has 2 divisors, whose sum is σ = 189662. Its totient is φ = 189660.

The previous prime is 189653. The next prime is 189671. The reversal of 189661 is 166981.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 184900 + 4761 = 430^2 + 69^2 .

It is a cyclic number.

It is not a de Polignac number, because 189661 - 2³ = 189653 is a prime.

It is an Ulam number.

It is the 436-th Hogben number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (189671) by changing a digit.

It is a nontrivial repunit in base 435.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 94830 + 94831.

It is an arithmetic number, because the mean of its divisors is an integer number (94831).

2¹⁸⁹⁶⁶¹ is an apocalyptic number.

It is an amenable number.

189661 is a deficient number, since it is larger than the sum of its proper divisors (1).

189661 is an equidigital number, since it uses as much as digits as its factorization.

189661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2592, while the sum is 31.

The square root of 189661 is about 435.5008610784. The cubic root of 189661 is about 57.4547596258.

The spelling of 189661 in words is "one hundred eighty-nine thousand, six hundred sixty-one".