168191861 has 2 divisors, whose sum is σ = 168191862. Its totient is φ = 168191860.

The previous prime is 168191839. The next prime is 168191867.

168191861 is nontrivially palindromic in base 10.

168191861 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 93973636 + 74218225 = 9694^2 + 8615^2 .

It is a palprime.

It is a cyclic number.

It is not a de Polignac number, because 168191861 - 2⁶ = 168191797 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (168191867) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 84095930 + 84095931.

It is an arithmetic number, because the mean of its divisors is an integer number (84095931).

Almost surely, 2^168191861 is an apocalyptic number.

It is an amenable number.

168191861 is a deficient number, since it is larger than the sum of its proper divisors (1).

168191861 is an equidigital number, since it uses as much as digits as its factorization.

168191861 is an evil number, because the sum of its binary digits is even.

The product of its digits is 20736, while the sum is 41.

The square root of 168191861 is about 12968.8804836809. The cubic root of 168191861 is about 551.9948069332.

The spelling of 168191861 in words is "one hundred sixty-eight million, one hundred ninety-one thousand, eight hundred sixty-one".