661189 has 2 divisors, whose sum is σ = 661190. Its totient is φ = 661188.

The previous prime is 661187. The next prime is 661201. The reversal of 661189 is 981166.

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., 588289 + 72900 = 767^2 + 270^2 .

It is a cyclic number.

It is not a de Polignac number, because 661189 - 2¹ = 661187 is a prime.

Together with 661187, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 661189.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (661183) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330594 + 330595.

It is an arithmetic number, because the mean of its divisors is an integer number (330595).

2⁶⁶¹¹⁸⁹ is an apocalyptic number.

It is an amenable number.

661189 is a deficient number, since it is larger than the sum of its proper divisors (1).

661189 is an equidigital number, since it uses as much as digits as its factorization.

661189 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 661189 is about 813.1352900963. The cubic root of 661189 is about 87.1181290454.

The spelling of 661189 in words is "six hundred sixty-one thousand, one hundred eighty-nine".