663709 has 2 divisors, whose sum is σ = 663710. Its totient is φ = 663708.

The previous prime is 663683. The next prime is 663713. The reversal of 663709 is 907366.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 632025 + 31684 = 795^2 + 178^2 .

It is a cyclic number.

It is not a de Polignac number, because 663709 - 2⁷ = 663581 is a prime.

It is an Ulam number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (663209) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 331854 + 331855.

It is an arithmetic number, because the mean of its divisors is an integer number (331855).

2⁶⁶³⁷⁰⁹ is an apocalyptic number.

It is an amenable number.

663709 is a deficient number, since it is larger than the sum of its proper divisors (1).

663709 is an equidigital number, since it uses as much as digits as its factorization.

663709 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6804, while the sum is 31.

The square root of 663709 is about 814.6833740785. The cubic root of 663709 is about 87.2286669628.

The spelling of 663709 in words is "six hundred sixty-three thousand, seven hundred nine".