66647797 has 4 divisors (see below), whose sum is σ = 67491520. Its totient is φ = 65804076.

The previous prime is 66647783. The next prime is 66647809. The reversal of 66647797 is 79774666.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 66647797 - 2²³ = 58259189 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66647717) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 421743 + ... + 421900.

It is an arithmetic number, because the mean of its divisors is an integer number (16872880).

Almost surely, 2^66647797 is an apocalyptic number.

It is an amenable number.

66647797 is a deficient number, since it is larger than the sum of its proper divisors (843723).

66647797 is an equidigital number, since it uses as much as digits as its factorization.

66647797 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 843722.

The product of its digits is 2667168, while the sum is 52.

The square root of 66647797 is about 8163.8102011255. The cubic root of 66647797 is about 405.4418730535.

The spelling of 66647797 in words is "sixty-six million, six hundred forty-seven thousand, seven hundred ninety-seven".