Multipling 40656 by its sum of digits (21), we get a square (853776 = 9242).
40656 divided by its sum of digits (21) gives a square (1936 = 442).
40656 is digitally balanced in base 2 and base 4, because in such bases it contains all the possibile digits an equal number of times.
It is a congruent number.
It is an unprimeable number.
40656 is an untouchable number, because it is not equal to the sum of proper divisors of any number.
240656 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 40656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (65968).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
40656 is a wasteful number, since it uses less digits than its factorization.
40656 is an evil number, because the sum of its binary digits is even.
The square root of 40656 is about 201.6333305781. The cubic root of 40656 is about 34.3854634813.
The spelling of 40656 in words is "forty thousand, six hundred fifty-six".