188131661 has 2 divisors, whose sum is σ = 188131662. Its totient is φ = 188131660.

The previous prime is 188131649. The next prime is 188131733. The reversal of 188131661 is 166131881.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 143161225 + 44970436 = 11965^2 + 6706^2 .

It is an emirp because it is prime and its reverse (166131881) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 188131661 - 2¹⁰ = 188130637 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (188131861) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 94065830 + 94065831.

It is an arithmetic number, because the mean of its divisors is an integer number (94065831).

Almost surely, 2^188131661 is an apocalyptic number.

It is an amenable number.

188131661 is a deficient number, since it is larger than the sum of its proper divisors (1).

188131661 is an equidigital number, since it uses as much as digits as its factorization.

188131661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6912, while the sum is 35.

The square root of 188131661 is about 13716.1095431613. The cubic root of 188131661 is about 572.9991309517. Note that the first 3 decimals are identical.

The spelling of 188131661 in words is "one hundred eighty-eight million, one hundred thirty-one thousand, six hundred sixty-one".