664609397 has 2 divisors, whose sum is σ = 664609398. Its totient is φ = 664609396.

The previous prime is 664609367. The next prime is 664609459. The reversal of 664609397 is 793906466.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 521711281 + 142898116 = 22841^2 + 11954^2 .

It is a cyclic number.

It is not a de Polignac number, because 664609397 - 2¹⁸ = 664347253 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (664609307) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332304698 + 332304699.

It is an arithmetic number, because the mean of its divisors is an integer number (332304699).

Almost surely, 2^664609397 is an apocalyptic number.

It is an amenable number.

664609397 is a deficient number, since it is larger than the sum of its proper divisors (1).

664609397 is an equidigital number, since it uses as much as digits as its factorization.

664609397 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1469664, while the sum is 50.

The square root of 664609397 is about 25780.0193366879. The cubic root of 664609397 is about 872.6809435262.

It can be divided in two parts, 66460 and 9397, that added together give a palindrome (75857).

The spelling of 664609397 in words is "six hundred sixty-four million, six hundred nine thousand, three hundred ninety-seven".