656240 has 40 divisors (see below), whose sum is σ = 1645728. Its totient is φ = 241920.

The previous prime is 656237. The next prime is 656263. The reversal of 656240 is 42656.

Added to its reverse (42656) it gives a square (698896 = 836²).

It is a tau number, because it is divible by the number of its divisors (40).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 725 + ... + 1355.

2⁶⁵⁶²⁴⁰ 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 656240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (822864).

656240 is an abundant number, since it is smaller than the sum of its proper divisors (989488).

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

656240 is a wasteful number, since it uses less digits than its factorization.

656240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 657 (or 651 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 23.

The square root of 656240 is about 810.0864151435. The cubic root of 656240 is about 86.9002247197.

Adding to 656240 its reverse (42656), we get a palindrome (698896).

The spelling of 656240 in words is "six hundred fifty-six thousand, two hundred forty".