656404 has 36 divisors (see below), whose sum is σ = 1422036. Its totient is φ = 263424.

The previous prime is 656389. The next prime is 656407. The reversal of 656404 is 404656.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 592900 + 63504 = 770^2 + 252^2 .

It is a super-2 number, since 2×656404² = 861732422432, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (656407) by changing a digit.

656404 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

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 in 11 ways as a sum of consecutive naturals, for example, 3234 + ... + 3430.

It is an arithmetic number, because the mean of its divisors is an integer number (39501).

2⁶⁵⁶⁴⁰⁴ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 656404, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (711018).

656404 is an abundant number, since it is smaller than the sum of its proper divisors (765632).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

656404 is a wasteful number, since it uses less digits than its factorization.

656404 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 232 (or 223 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 25.

The square root of 656404 is about 810.1876325889. The cubic root of 656404 is about 86.9074631537.

The spelling of 656404 in words is "six hundred fifty-six thousand, four hundred four".