66649199 has 4 divisors (see below), whose sum is σ = 67048464. Its totient is φ = 66249936.

The previous prime is 66649159. The next prime is 66649201. The reversal of 66649199 is 99194666.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 66649199 - 2¹⁶ = 66583663 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66649109) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 199382 + ... + 199715.

It is an arithmetic number, because the mean of its divisors is an integer number (16762116).

Almost surely, 2^66649199 is an apocalyptic number.

66649199 is a deficient number, since it is larger than the sum of its proper divisors (399265).

66649199 is a wasteful number, since it uses less digits than its factorization.

66649199 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 399264.

The product of its digits is 629856, while the sum is 50.

The square root of 66649199 is about 8163.8960674423. The cubic root of 66649199 is about 405.4447159858. Note that the first 3 decimals are identical.

The spelling of 66649199 in words is "sixty-six million, six hundred forty-nine thousand, one hundred ninety-nine".