188806561 has 2 divisors, whose sum is σ = 188806562. Its totient is φ = 188806560.

The previous prime is 188806547. The next prime is 188806571. The reversal of 188806561 is 165608881.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 168194961 + 20611600 = 12969^2 + 4540^2 .

It is a cyclic number.

It is not a de Polignac number, because 188806561 - 2⁷ = 188806433 is a prime.

It is not a weakly prime, because it can be changed into another prime (188806571) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 94403280 + 94403281.

It is an arithmetic number, because the mean of its divisors is an integer number (94403281).

Almost surely, 2^188806561 is an apocalyptic number.

It is an amenable number.

188806561 is a deficient number, since it is larger than the sum of its proper divisors (1).

188806561 is an equidigital number, since it uses as much as digits as its factorization.

188806561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 92160, while the sum is 43.

The square root of 188806561 is about 13740.6899753979. The cubic root of 188806561 is about 573.6835020227.

The spelling of 188806561 in words is "one hundred eighty-eight million, eight hundred six thousand, five hundred sixty-one".