66544777 has 4 divisors (see below), whose sum is σ = 71663620. Its totient is φ = 61425936.

The previous prime is 66544769. The next prime is 66544787. The reversal of 66544777 is 77744566.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 77744566 = 2 ⋅38872283.

It can be written as a sum of positive squares in 2 ways, for example, as 27657081 + 38887696 = 5259^2 + 6236^2 .

It is not a de Polignac number, because 66544777 - 2³ = 66544769 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66544787) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2559402 + ... + 2559427.

It is an arithmetic number, because the mean of its divisors is an integer number (17915905).

Almost surely, 2^66544777 is an apocalyptic number.

It is an amenable number.

66544777 is a deficient number, since it is larger than the sum of its proper divisors (5118843).

66544777 is a wasteful number, since it uses less digits than its factorization.

66544777 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5118842.

The product of its digits is 987840, while the sum is 46.

The square root of 66544777 is about 8157.4982071711. The cubic root of 66544777 is about 405.2328630874.

The spelling of 66544777 in words is "sixty-six million, five hundred forty-four thousand, seven hundred seventy-seven".