664097761 has 2 divisors, whose sum is σ = 664097762. Its totient is φ = 664097760.

The previous prime is 664097743. The next prime is 664097801. The reversal of 664097761 is 167790466.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 504227025 + 159870736 = 22455^2 + 12644^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-664097761 is a prime.

It is not a weakly prime, because it can be changed into another prime (664097701) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332048880 + 332048881.

It is an arithmetic number, because the mean of its divisors is an integer number (332048881).

Almost surely, 2^664097761 is an apocalyptic number.

It is an amenable number.

664097761 is a deficient number, since it is larger than the sum of its proper divisors (1).

664097761 is an equidigital number, since it uses as much as digits as its factorization.

664097761 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 381024, while the sum is 46.

The square root of 664097761 is about 25770.0943149225. The cubic root of 664097761 is about 872.4569474902.

It can be divided in two parts, 6640 and 97761, that added together give a palindrome (104401).

The spelling of 664097761 in words is "six hundred sixty-four million, ninety-seven thousand, seven hundred sixty-one".