668761 has 2 divisors, whose sum is σ = 668762. Its totient is φ = 668760.

The previous prime is 668747. The next prime is 668791. The reversal of 668761 is 167866.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 648025 + 20736 = 805^2 + 144^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-668761 is a prime.

668761 is a lucky number.

It is not a weakly prime, because it can be changed into another prime (668741) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 334380 + 334381.

It is an arithmetic number, because the mean of its divisors is an integer number (334381).

2⁶⁶⁸⁷⁶¹ is an apocalyptic number.

It is an amenable number.

668761 is a deficient number, since it is larger than the sum of its proper divisors (1).

668761 is an equidigital number, since it uses as much as digits as its factorization.

668761 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12096, while the sum is 34.

The square root of 668761 is about 817.7780872584. The cubic root of 668761 is about 87.4494292816.

The spelling of 668761 in words is "six hundred sixty-eight thousand, seven hundred sixty-one".