66777770 has 8 divisors (see below), whose sum is σ = 120200004. Its totient is φ = 26711104.

The previous prime is 66777713. The next prime is 66777779. The reversal of 66777770 is 7777766.

It can be written as a sum of positive squares in 2 ways, for example, as 63952009 + 2825761 = 7997^2 + 1681^2 .

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

It is not an unprimeable number, because it can be changed into a prime (66777779) 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, 3338879 + ... + 3338898.

Almost surely, 2^66777770 is an apocalyptic number.

66777770 is a deficient number, since it is larger than the sum of its proper divisors (53422234).

66777770 is a wasteful number, since it uses less digits than its factorization.

66777770 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6677784.

The product of its (nonzero) digits is 605052, while the sum is 47.

The square root of 66777770 is about 8171.7666388609. The cubic root of 66777770 is about 405.7052589952.

It can be divided in two parts, 6 and 6777770, that added together give a palindrome (6777776).

The spelling of 66777770 in words is "sixty-six million, seven hundred seventy-seven thousand, seven hundred seventy".