168901661 has 2 divisors, whose sum is σ = 168901662. Its totient is φ = 168901660.

The previous prime is 168901643. The next prime is 168901679. The reversal of 168901661 is 166109861.

It is a balanced prime because it is at equal distance from previous prime (168901643) and next prime (168901679).

It can be written as a sum of positive squares in only one way, i.e., 90136036 + 78765625 = 9494^2 + 8875^2 .

It is an emirp because it is prime and its reverse (166109861) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 168901661 - 2¹⁸ = 168639517 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (168901631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 84450830 + 84450831.

It is an arithmetic number, because the mean of its divisors is an integer number (84450831).

Almost surely, 2^168901661 is an apocalyptic number.

It is an amenable number.

168901661 is a deficient number, since it is larger than the sum of its proper divisors (1).

168901661 is an equidigital number, since it uses as much as digits as its factorization.

168901661 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 15552, while the sum is 38.

The square root of 168901661 is about 12996.2171803952. The cubic root of 168901661 is about 552.7702230490.

The spelling of 168901661 in words is "one hundred sixty-eight million, nine hundred one thousand, six hundred sixty-one".