664444777 has 2 divisors, whose sum is σ = 664444778. Its totient is φ = 664444776.

The previous prime is 664444771. The next prime is 664444783. The reversal of 664444777 is 777444466.

It is a balanced prime because it is at equal distance from previous prime (664444771) and next prime (664444783).

It can be written as a sum of positive squares in only one way, i.e., 643687641 + 20757136 = 25371^2 + 4556^2 .

It is a cyclic number.

It is not a de Polignac number, because 664444777 - 2¹¹ = 664442729 is a prime.

It is a zygodrome in base 10.

It is a self number, because there is not a number n which added to its sum of digits gives 664444777.

It is not a weakly prime, because it can be changed into another prime (664444771) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332222388 + 332222389.

It is an arithmetic number, because the mean of its divisors is an integer number (332222389).

Almost surely, 2^664444777 is an apocalyptic number.

It is an amenable number.

664444777 is a deficient number, since it is larger than the sum of its proper divisors (1).

664444777 is an equidigital number, since it uses as much as digits as its factorization.

664444777 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3161088, while the sum is 49.

The square root of 664444777 is about 25776.8263562449. The cubic root of 664444777 is about 872.6088848601.

The spelling of 664444777 in words is "six hundred sixty-four million, four hundred forty-four thousand, seven hundred seventy-seven".