668950181 has 2 divisors, whose sum is σ = 668950182. Its totient is φ = 668950180.

The previous prime is 668950171. The next prime is 668950199. The reversal of 668950181 is 181059866.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 530887681 + 138062500 = 23041^2 + 11750^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-668950181 is a prime.

It is a super-2 number, since 2×668950181² = 894988689319865522, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (668950141) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 334475090 + 334475091.

It is an arithmetic number, because the mean of its divisors is an integer number (334475091).

Almost surely, 2^668950181 is an apocalyptic number.

It is an amenable number.

668950181 is a deficient number, since it is larger than the sum of its proper divisors (1).

668950181 is an equidigital number, since it uses as much as digits as its factorization.

668950181 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 103680, while the sum is 44.

The square root of 668950181 is about 25864.0712379161. The cubic root of 668950181 is about 874.5767448470.

The spelling of 668950181 in words is "six hundred sixty-eight million, nine hundred fifty thousand, one hundred eighty-one".