406681 has 6 divisors (see below), whose sum is σ = 447146. Its totient is φ = 369600.

The previous prime is 406673. The next prime is 406697. The reversal of 406681 is 186604.

406681 is an esthetic number in base 9, because in such base its adjacent digits differ by 1.

It can be written as a sum of positive squares in only one way, i.e., 379456 + 27225 = 616^2 + 165^2 .

It is not a de Polignac number, because 406681 - 2³ = 406673 is a prime.

It is a super-2 number, since 2×406681² = 330778871522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (406631) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1560 + ... + 1801.

2⁴⁰⁶⁶⁸¹ is an apocalyptic number.

It is an amenable number.

406681 is a deficient number, since it is larger than the sum of its proper divisors (40465).

406681 is a wasteful number, since it uses less digits than its factorization.

406681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3383 (or 3372 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 25.

The square root of 406681 is about 637.7154537880. The cubic root of 406681 is about 74.0885839570.

The spelling of 406681 in words is "four hundred six thousand, six hundred eighty-one".