6640930 has 16 divisors (see below), whose sum is σ = 12036600. Its totient is φ = 2637952.

The previous prime is 6640927. The next prime is 6640939. The reversal of 6640930 is 390466.

It is a Cunningham number, because it is equal to 2577²+1.

It can be written as a sum of positive squares in 4 ways, for example, as 4661281 + 1979649 = 2159^2 + 1407^2 .

It is an Ulam number.

It is a nialpdrome in base 16.

It is not an unprimeable number, because it can be changed into a prime (6640939) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 739 + ... + 3718.

Almost surely, 2^6640930 is an apocalyptic number.

6640930 is a deficient number, since it is larger than the sum of its proper divisors (5395670).

6640930 is a wasteful number, since it uses less digits than its factorization.

6640930 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4613.

The product of its (nonzero) digits is 3888, while the sum is 28.

The square root of 6640930 is about 2577.0001940241. Note that the first 3 decimals coincide. The cubic root of 6640930 is about 187.9647021402.

The spelling of 6640930 in words is "six million, six hundred forty thousand, nine hundred thirty".