663557 has 2 divisors, whose sum is σ = 663558. Its totient is φ = 663556.

The previous prime is 663547. The next prime is 663563. The reversal of 663557 is 755366.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 662596 + 961 = 814^2 + 31^2 .

It is a cyclic number.

It is not a de Polignac number, because 663557 - 2⁴ = 663541 is a prime.

It is a Chen 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 (663517) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 331778 + 331779.

It is an arithmetic number, because the mean of its divisors is an integer number (331779).

2⁶⁶³⁵⁵⁷ is an apocalyptic number.

It is an amenable number.

663557 is a deficient number, since it is larger than the sum of its proper divisors (1).

663557 is an equidigital number, since it uses as much as digits as its factorization.

663557 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 18900, while the sum is 32.

The square root of 663557 is about 814.5900809610. The cubic root of 663557 is about 87.2220075334. Note that the first 3 decimals are identical.

Subtracting 663557 from its reverse (755366), we obtain a square (91809 = 303²).

The spelling of 663557 in words is "six hundred sixty-three thousand, five hundred fifty-seven".