6398666 has 4 divisors (see below), whose sum is σ = 9598002. Its totient is φ = 3199332.

The previous prime is 6398633. The next prime is 6398671. The reversal of 6398666 is 6668936.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 6325225 + 73441 = 2515^2 + 271^2 .

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1599665 + ... + 1599668.

Almost surely, 2^6398666 is an apocalyptic number.

6398666 is a deficient number, since it is larger than the sum of its proper divisors (3199336).

6398666 is a wasteful number, since it uses less digits than its factorization.

6398666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3199335.

The product of its digits is 279936, while the sum is 44.

The square root of 6398666 is about 2529.5584594945. The cubic root of 6398666 is about 185.6506526992.

The spelling of 6398666 in words is "six million, three hundred ninety-eight thousand, six hundred sixty-six".