66719761 has 4 divisors (see below), whose sum is σ = 66883300. Its totient is φ = 66556224.

The previous prime is 66719753. The next prime is 66719771. The reversal of 66719761 is 16791766.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 40259025 + 26460736 = 6345^2 + 5144^2 .

It is a cyclic number.

It is not a de Polignac number, because 66719761 - 2³ = 66719753 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66719771) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 81156 + ... + 81973.

It is an arithmetic number, because the mean of its divisors is an integer number (16720825).

Almost surely, 2^66719761 is an apocalyptic number.

It is an amenable number.

66719761 is a deficient number, since it is larger than the sum of its proper divisors (163539).

66719761 is a wasteful number, since it uses less digits than its factorization.

66719761 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 163538.

The product of its digits is 95256, while the sum is 43.

The square root of 66719761 is about 8168.2165128013. The cubic root of 66719761 is about 405.5877479613.

The spelling of 66719761 in words is "sixty-six million, seven hundred nineteen thousand, seven hundred sixty-one".