6640186 has 12 divisors (see below), whose sum is σ = 11586618. Its totient is φ = 2845752.

The previous prime is 6640181. The next prime is 6640213. The reversal of 6640186 is 6810466.

It can be written as a sum of positive squares in only one way, i.e., 3980025 + 2660161 = 1995^2 + 1631^2 .

It is a super-2 number, since 2×6640186² = 88184140229192, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (6640181) 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, 33781 + ... + 33976.

Almost surely, 2^6640186 is an apocalyptic number.

6640186 is a deficient number, since it is larger than the sum of its proper divisors (4946432).

6640186 is a wasteful number, since it uses less digits than its factorization.

6640186 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 67773 (or 67766 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 31.

The square root of 6640186 is about 2576.8558360917. The cubic root of 6640186 is about 187.9576824928.

The spelling of 6640186 in words is "six million, six hundred forty thousand, one hundred eighty-six".