66575657 has 2 divisors, whose sum is σ = 66575658. Its totient is φ = 66575656.

The previous prime is 66575623. The next prime is 66575669. The reversal of 66575657 is 75657566.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 64947481 + 1628176 = 8059^2 + 1276^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66575657 is a prime.

It is not a weakly prime, because it can be changed into another prime (66575687) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33287828 + 33287829.

It is an arithmetic number, because the mean of its divisors is an integer number (33287829).

Almost surely, 2^66575657 is an apocalyptic number.

It is an amenable number.

66575657 is a deficient number, since it is larger than the sum of its proper divisors (1).

66575657 is an equidigital number, since it uses as much as digits as its factorization.

66575657 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1323000, while the sum is 47.

The square root of 66575657 is about 8159.3907248029. The cubic root of 66575657 is about 405.2955359534.

The spelling of 66575657 in words is "sixty-six million, five hundred seventy-five thousand, six hundred fifty-seven".