664666577 has 2 divisors, whose sum is σ = 664666578. Its totient is φ = 664666576.

The previous prime is 664666547. The next prime is 664666643. The reversal of 664666577 is 775666466.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 553237441 + 111429136 = 23521^2 + 10556^2 .

It is a cyclic number.

It is not a de Polignac number, because 664666577 - 2¹⁰ = 664665553 is a prime.

It is not a weakly prime, because it can be changed into another prime (664666537) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332333288 + 332333289.

It is an arithmetic number, because the mean of its divisors is an integer number (332333289).

Almost surely, 2^664666577 is an apocalyptic number.

It is an amenable number.

664666577 is a deficient number, since it is larger than the sum of its proper divisors (1).

664666577 is an equidigital number, since it uses as much as digits as its factorization.

664666577 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7620480, while the sum is 53.

The square root of 664666577 is about 25781.1283112280. The cubic root of 664666577 is about 872.7059699882.

The spelling of 664666577 in words is "six hundred sixty-four million, six hundred sixty-six thousand, five hundred seventy-seven".