66197977 has 2 divisors, whose sum is σ = 66197978. Its totient is φ = 66197976.

The previous prime is 66197969. The next prime is 66198019. The reversal of 66197977 is 77979166.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 66194496 + 3481 = 8136^2 + 59^2 .

It is a cyclic number.

It is not a de Polignac number, because 66197977 - 2³ = 66197969 is a prime.

It is not a weakly prime, because it can be changed into another prime (66197917) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33098988 + 33098989.

It is an arithmetic number, because the mean of its divisors is an integer number (33098989).

Almost surely, 2^66197977 is an apocalyptic number.

It is an amenable number.

66197977 is a deficient number, since it is larger than the sum of its proper divisors (1).

66197977 is an equidigital number, since it uses as much as digits as its factorization.

66197977 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1000188, while the sum is 52.

The square root of 66197977 is about 8136.2139229497. The cubic root of 66197977 is about 404.5276757624.

The spelling of 66197977 in words is "sixty-six million, one hundred ninety-seven thousand, nine hundred seventy-seven".