656669 has 4 divisors (see below), whose sum is σ = 707196. Its totient is φ = 606144.

The previous prime is 656657. The next prime is 656671. The reversal of 656669 is 966656.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 375769 + 280900 = 613^2 + 530^2 .

It is a cyclic number.

It is not a de Polignac number, because 656669 - 2¹² = 652573 is a prime.

It is a super-2 number, since 2×656669² = 862428351122, which contains 22 as substring.

It is an Ulam number.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (656609) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 25244 + ... + 25269.

It is an arithmetic number, because the mean of its divisors is an integer number (176799).

2⁶⁵⁶⁶⁶⁹ is an apocalyptic number.

It is an amenable number.

656669 is a deficient number, since it is larger than the sum of its proper divisors (50527).

656669 is a wasteful number, since it uses less digits than its factorization.

656669 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50526.

The product of its digits is 58320, while the sum is 38.

The square root of 656669 is about 810.3511584492. The cubic root of 656669 is about 86.9191568562.

The spelling of 656669 in words is "six hundred fifty-six thousand, six hundred sixty-nine".