401666 has 8 divisors (see below), whose sum is σ = 605820. Its totient is φ = 199728.

The previous prime is 401651. The next prime is 401669. The reversal of 401666 is 666104.

It can be written as a sum of positive squares in 2 ways, for example, as 326041 + 75625 = 571^2 + 275^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-2 number, since 2×401666² = 322671151112, which contains 22 as substring.

It is a Curzon number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 401666.

It is not an unprimeable number, because it can be changed into a prime (401669) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 20 + ... + 896.

2⁴⁰¹⁶⁶⁶ is an apocalyptic number.

401666 is a deficient number, since it is larger than the sum of its proper divisors (204154).

401666 is a wasteful number, since it uses less digits than its factorization.

401666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1108.

The product of its (nonzero) digits is 864, while the sum is 23.

The square root of 401666 is about 633.7712521092. The cubic root of 401666 is about 73.7827815580.

The spelling of 401666 in words is "four hundred one thousand, six hundred sixty-six".