66789999 has 24 divisors (see below), whose sum is σ = 101092992. Its totient is φ = 42411600.

The previous prime is 66789979. The next prime is 66790007. The reversal of 66789999 is 99998766.

It is not a de Polignac number, because 66789999 - 2⁵ = 66789967 is a prime.

66789999 is a modest number, since divided by 9999 gives 6678 as remainder.

It is a plaindrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66789949) 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 23 ways as a sum of consecutive naturals, for example, 63024 + ... + 64074.

It is an arithmetic number, because the mean of its divisors is an integer number (4212208).

Almost surely, 2^66789999 is an apocalyptic number.

66789999 is a gapful number since it is divisible by the number (69) formed by its first and last digit.

66789999 is a deficient number, since it is larger than the sum of its proper divisors (34302993).

66789999 is a wasteful number, since it uses less digits than its factorization.

66789999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1387 (or 1384 counting only the distinct ones).

The product of its digits is 13226976, while the sum is 63.

The square root of 66789999 is about 8172.5148516231. The cubic root of 66789999 is about 405.7300230586.

The spelling of 66789999 in words is "sixty-six million, seven hundred eighty-nine thousand, nine hundred ninety-nine".