6491666 has 4 divisors (see below), whose sum is σ = 9737502. Its totient is φ = 3245832.

The previous prime is 6491663. The next prime is 6491669. The reversal of 6491666 is 6661946.

6491666 = 730² + 731² + ... + 741².

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 6661946 = 2 ⋅3330973.

It is an interprime number because it is at equal distance from previous prime (6491663) and next prime (6491669).

It can be written as a sum of positive squares in only one way, i.e., 6477025 + 14641 = 2545^2 + 121^2 .

It is not an unprimeable number, because it can be changed into a prime (6491663) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1622915 + ... + 1622918.

Almost surely, 2^6491666 is an apocalyptic number.

6491666 is a deficient number, since it is larger than the sum of its proper divisors (3245836).

6491666 is a wasteful number, since it uses less digits than its factorization.

6491666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3245835.

The product of its digits is 46656, while the sum is 38.

The square root of 6491666 is about 2547.8748006917. The cubic root of 6491666 is about 186.5457628357.

The spelling of 6491666 in words is "six million, four hundred ninety-one thousand, six hundred sixty-six".