4006681 has 6 divisors (see below), whose sum is σ = 4660890. Its totient is φ = 3434256.

The previous prime is 4006661. The next prime is 4006687. The reversal of 4006681 is 1866004.

4006681 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 2752281 + 1254400 = 1659^2 + 1120^2 .

It is not a de Polignac number, because 4006681 - 2⁵ = 4006649 is a prime.

It is a super-2 number, since 2×4006681² = 32106985271522, which contains 22 as substring.

It is an Ulam number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (4006687) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 40836 + ... + 40933.

It is an arithmetic number, because the mean of its divisors is an integer number (776815).

Almost surely, 2^4006681 is an apocalyptic number.

It is an amenable number.

4006681 is a deficient number, since it is larger than the sum of its proper divisors (654209).

4006681 is an equidigital number, since it uses as much as digits as its factorization.

4006681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81783 (or 81776 counting only the distinct ones).

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

The square root of 4006681 is about 2001.6695531481. The cubic root of 4006681 is about 158.8284345912.

The spelling of 4006681 in words is "four million, six thousand, six hundred eighty-one".