664666477 has 2 divisors, whose sum is σ = 664666478. Its totient is φ = 664666476.

The previous prime is 664666463. The next prime is 664666529. The reversal of 664666477 is 774666466.

It is a happy number.

664666477 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an a-pointer prime, because the next prime (664666529) can be obtained adding 664666477 to its sum of digits (52).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 632472201 + 32194276 = 25149^2 + 5674^2 .

It is a cyclic number.

It is not a de Polignac number, because 664666477 - 2⁷ = 664666349 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (664666577) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332333238 + 332333239.

It is an arithmetic number, because the mean of its divisors is an integer number (332333239).

Almost surely, 2^664666477 is an apocalyptic number.

It is an amenable number.

664666477 is a deficient number, since it is larger than the sum of its proper divisors (1).

664666477 is an equidigital number, since it uses as much as digits as its factorization.

664666477 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6096384, while the sum is 52.

The square root of 664666477 is about 25781.1263718248. The cubic root of 664666477 is about 872.7059262216.

The spelling of 664666477 in words is "six hundred sixty-four million, six hundred sixty-six thousand, four hundred seventy-seven".