66197251 has 4 divisors (see below), whose sum is σ = 66275352. Its totient is φ = 66119152.

The previous prime is 66197237. The next prime is 66197267. The reversal of 66197251 is 15279166.

66197251 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a cyclic number.

It is not a de Polignac number, because 66197251 - 2⁷ = 66197123 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 66197251.

It is not an unprimeable number, because it can be changed into a prime (66197281) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 37765 + ... + 39478.

It is an arithmetic number, because the mean of its divisors is an integer number (16568838).

Almost surely, 2^66197251 is an apocalyptic number.

66197251 is a deficient number, since it is larger than the sum of its proper divisors (78101).

66197251 is an equidigital number, since it uses as much as digits as its factorization.

66197251 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 78100.

The product of its digits is 22680, while the sum is 37.

The square root of 66197251 is about 8136.1693074813. The cubic root of 66197251 is about 404.5261969249.

The spelling of 66197251 in words is "sixty-six million, one hundred ninety-seven thousand, two hundred fifty-one".