403866 has 28 divisors (see below), whose sum is σ = 911562. Its totient is φ = 134136.

The previous prime is 403861. The next prime is 403867. The reversal of 403866 is 668304.

It can be written as a sum of positive squares in only one way, i.e., 385641 + 18225 = 621^2 + 135^2 .

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an Ulam number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (403861) by changing a digit.

It is a polite number, since it can be written in 13 ways as a sum of consecutive naturals, for example, 1320 + ... + 1596.

2⁴⁰³⁸⁶⁶ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 403866, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (455781).

403866 is an abundant number, since it is smaller than the sum of its proper divisors (507696).

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

403866 is an equidigital number, since it uses as much as digits as its factorization.

403866 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 297 (or 282 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 27.

The square root of 403866 is about 635.5045239808. The cubic root of 403866 is about 73.9172437410.

The spelling of 403866 in words is "four hundred three thousand, eight hundred sixty-six".