647557 has 2 divisors, whose sum is σ = 647558. Its totient is φ = 647556.

The previous prime is 647551. The next prime is 647579. The reversal of 647557 is 755746.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 370881 + 276676 = 609^2 + 526^2 .

It is a cyclic number.

It is not a de Polignac number, because 647557 - 2⁷ = 647429 is a prime.

647557 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (647551) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323778 + 323779.

It is an arithmetic number, because the mean of its divisors is an integer number (323779).

2⁶⁴⁷⁵⁵⁷ is an apocalyptic number.

It is an amenable number.

647557 is a deficient number, since it is larger than the sum of its proper divisors (1).

647557 is an equidigital number, since it uses as much as digits as its factorization.

647557 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 29400, while the sum is 34.

The square root of 647557 is about 804.7092642688. The cubic root of 647557 is about 86.5152500761.

The spelling of 647557 in words is "six hundred forty-seven thousand, five hundred fifty-seven".