405656 has 8 divisors (see below), whose sum is σ = 760620. Its totient is φ = 202824.

The previous prime is 405641. The next prime is 405659. The reversal of 405656 is 656504.

It is a tau number, because it is divible by the number of its divisors (8).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (405659) by changing a digit.

405656 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 (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25346 + ... + 25361.

2⁴⁰⁵⁶⁵⁶ is an apocalyptic number.

It is an amenable number.

405656 is a deficient number, since it is larger than the sum of its proper divisors (354964).

405656 is a wasteful number, since it uses less digits than its factorization.

405656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50713 (or 50709 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 26.

The square root of 405656 is about 636.9112968067. The cubic root of 405656 is about 74.0262872276.

The spelling of 405656 in words is "four hundred five thousand, six hundred fifty-six".