66779999 has 16 divisors (see below), whose sum is σ = 78702624. Its totient is φ = 55862400.

The previous prime is 66779987. The next prime is 66780031. The reversal of 66779999 is 99997766.

It is a de Polignac number, because none of the positive numbers 2^k-66779999 is a prime.

66779999 is a modest number, since divided by 9999 gives 6677 as remainder.

It is a plaindrome in base 10.

It is a zygodrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66779969) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 65417 + ... + 66429.

It is an arithmetic number, because the mean of its divisors is an integer number (4918914).

Almost surely, 2^66779999 is an apocalyptic number.

66779999 is a deficient number, since it is larger than the sum of its proper divisors (11922625).

66779999 is a wasteful number, since it uses less digits than its factorization.

66779999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1498.

The product of its digits is 11573604, while the sum is 62.

The square root of 66779999 is about 8171.9030219405. The cubic root of 66779999 is about 405.7097730072.

The spelling of 66779999 in words is "sixty-six million, seven hundred seventy-nine thousand, nine hundred ninety-nine".