667557 has 18 divisors (see below), whose sum is σ = 1061606. Its totient is φ = 403920.

The previous prime is 667553. The next prime is 667559. The reversal of 667557 is 755766.

It can be written as a sum of positive squares in only one way, i.e., 352836 + 314721 = 594^2 + 561^2 .

It is not a de Polignac number, because 667557 - 2² = 667553 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (667553) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 783 + ... + 1395.

2⁶⁶⁷⁵⁵⁷ is an apocalyptic number.

It is an amenable number.

667557 is a deficient number, since it is larger than the sum of its proper divisors (394049).

667557 is a wasteful number, since it uses less digits than its factorization.

667557 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 641 (or 627 counting only the distinct ones).

The product of its digits is 44100, while the sum is 36.

The square root of 667557 is about 817.0416146072. The cubic root of 667557 is about 87.3969180648.

Subtracting 667557 from its reverse (755766), we obtain a square (88209 = 297²).

The spelling of 667557 in words is "six hundred sixty-seven thousand, five hundred fifty-seven".