6499666 has 4 divisors (see below), whose sum is σ = 9749502. Its totient is φ = 3249832.

The previous prime is 6499663. The next prime is 6499667. The reversal of 6499666 is 6669946.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 6669946 = 2 ⋅3334973.

It can be written as a sum of positive squares in only one way, i.e., 6426225 + 73441 = 2535^2 + 271^2 .

It is a super-2 number, since 2×6499666² = 84491316223112, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (6499663) 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 as a sum of consecutive naturals, namely, 1624915 + ... + 1624918.

Almost surely, 2^6499666 is an apocalyptic number.

6499666 is a deficient number, since it is larger than the sum of its proper divisors (3249836).

6499666 is a wasteful number, since it uses less digits than its factorization.

6499666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3249835.

The product of its digits is 419904, while the sum is 46.

The square root of 6499666 is about 2549.4442531658. Note that the first 3 decimals coincide. The cubic root of 6499666 is about 186.6223612253.

The spelling of 6499666 in words is "six million, four hundred ninety-nine thousand, six hundred sixty-six".