6640001 has 4 divisors (see below), whose sum is σ = 6682452. Its totient is φ = 6597552.

The previous prime is 6639989. The next prime is 6640003. The reversal of 6640001 is 1000466.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1000466 = 2 ⋅500233.

It can be written as a sum of positive squares in 2 ways, for example, as 1795600 + 4844401 = 1340^2 + 2201^2 .

It is a cyclic number.

It is not a de Polignac number, because 6640001 - 2⁶ = 6639937 is a prime.

It is a super-2 number, since 2×6640001² = 88179226560002, 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 (6640003) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20990 + ... + 21303.

It is an arithmetic number, because the mean of its divisors is an integer number (1670613).

Almost surely, 2^6640001 is an apocalyptic number.

It is an amenable number.

6640001 is a deficient number, since it is larger than the sum of its proper divisors (42451).

6640001 is a wasteful number, since it uses less digits than its factorization.

6640001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42450.

The product of its (nonzero) digits is 144, while the sum is 17.

The square root of 6640001 is about 2576.8199393826. The cubic root of 6640001 is about 187.9559369346.

Adding to 6640001 its reverse (1000466), we get a palindrome (7640467).

The spelling of 6640001 in words is "six million, six hundred forty thousand, one".