66599977 has 2 divisors, whose sum is σ = 66599978. Its totient is φ = 66599976.

The previous prime is 66599971. The next prime is 66599989. The reversal of 66599977 is 77999566.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 63696361 + 2903616 = 7981^2 + 1704^2 .

It is a cyclic number.

It is not a de Polignac number, because 66599977 - 2³ = 66599969 is a prime.

It is not a weakly prime, because it can be changed into another prime (66599971) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33299988 + 33299989.

It is an arithmetic number, because the mean of its divisors is an integer number (33299989).

Almost surely, 2^66599977 is an apocalyptic number.

It is an amenable number.

66599977 is a deficient number, since it is larger than the sum of its proper divisors (1).

66599977 is an equidigital number, since it uses as much as digits as its factorization.

66599977 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6429780, while the sum is 58.

The square root of 66599977 is about 8160.8808960798. The cubic root of 66599977 is about 405.3448812542.

It can be divided in two parts, 66599 and 977, that added together give a palindrome (67576).

The spelling of 66599977 in words is "sixty-six million, five hundred ninety-nine thousand, nine hundred seventy-seven".