66999666 has 8 divisors (see below), whose sum is σ = 133999344. Its totient is φ = 22333220.

The previous prime is 66999661. The next prime is 66999689. The reversal of 66999666 is 66699966.

It is a sphenic number, since it is the product of 3 distinct primes.

66999666 is an admirable number.

It is a super-2 number, since 2×66999666² = 8977910488223112, which contains 22 as substring.

It is a zygodrome in base 10.

It is not an unprimeable number, because it can be changed into a prime (66999661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5583300 + ... + 5583311.

It is an arithmetic number, because the mean of its divisors is an integer number (16749918).

Almost surely, 2^66999666 is an apocalyptic number.

66999666 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

66999666 is a wasteful number, since it uses less digits than its factorization.

66999666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11166616.

The product of its digits is 5668704, while the sum is 57.

The square root of 66999666 is about 8185.3323695498. The cubic root of 66999666 is about 406.1541351394.

It can be divided in two parts, 66 and 999666, that multiplied together give a palindrome (65977956).

The spelling of 66999666 in words is "sixty-six million, nine hundred ninety-nine thousand, six hundred sixty-six".