65998666 has 16 divisors (see below), whose sum is σ = 104760000. Its totient is φ = 31097088.

The previous prime is 65998663. The next prime is 65998687. The reversal of 65998666 is 66689956.

It is not an unprimeable number, because it can be changed into a prime (65998663) 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, 2835 + ... + 11833.

It is an arithmetic number, because the mean of its divisors is an integer number (6547500).

Almost surely, 2^65998666 is an apocalyptic number.

65998666 is a deficient number, since it is larger than the sum of its proper divisors (38761334).

65998666 is a wasteful number, since it uses less digits than its factorization.

65998666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9213.

The product of its digits is 4199040, while the sum is 55.

The square root of 65998666 is about 8123.9563021966. The cubic root of 65998666 is about 404.1212793094.

The spelling of 65998666 in words is "sixty-five million, nine hundred ninety-eight thousand, six hundred sixty-six".