660281681 has 2 divisors, whose sum is σ = 660281682. Its totient is φ = 660281680.

The previous prime is 660281651. The next prime is 660281689. The reversal of 660281681 is 186182066.

660281681 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., 654899281 + 5382400 = 25591^2 + 2320^2 .

It is a cyclic number.

It is not a de Polignac number, because 660281681 - 2¹⁴ = 660265297 is a prime.

It is a super-2 number, since 2×660281681² = 871943796528371522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (660281689) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330140840 + 330140841.

It is an arithmetic number, because the mean of its divisors is an integer number (330140841).

Almost surely, 2^660281681 is an apocalyptic number.

It is an amenable number.

660281681 is a deficient number, since it is larger than the sum of its proper divisors (1).

660281681 is an equidigital number, since it uses as much as digits as its factorization.

660281681 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 27648, while the sum is 38.

The square root of 660281681 is about 25695.9467815451. The cubic root of 660281681 is about 870.7826141433.

The spelling of 660281681 in words is "six hundred sixty million, two hundred eighty-one thousand, six hundred eighty-one".