194989661 has 2 divisors, whose sum is σ = 194989662. Its totient is φ = 194989660.

The previous prime is 194989657. The next prime is 194989673. The reversal of 194989661 is 166989491.

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., 114618436 + 80371225 = 10706^2 + 8965^2 .

It is an emirp because it is prime and its reverse (166989491) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 194989661 - 2² = 194989657 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 (194989621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 97494830 + 97494831.

It is an arithmetic number, because the mean of its divisors is an integer number (97494831).

Almost surely, 2^194989661 is an apocalyptic number.

It is an amenable number.

194989661 is a deficient number, since it is larger than the sum of its proper divisors (1).

194989661 is an equidigital number, since it uses as much as digits as its factorization.

194989661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 839808, while the sum is 53.

The square root of 194989661 is about 13963.8698432777. The cubic root of 194989661 is about 579.8787509130.

The spelling of 194989661 in words is "one hundred ninety-four million, nine hundred eighty-nine thousand, six hundred sixty-one".