664405537 has 2 divisors, whose sum is σ = 664405538. Its totient is φ = 664405536.

The previous prime is 664405523. The next prime is 664405579. The reversal of 664405537 is 735504466.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 345997201 + 318408336 = 18601^2 + 17844^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-664405537 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 664405537.

It is not a weakly prime, because it can be changed into another prime (664400537) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332202768 + 332202769.

It is an arithmetic number, because the mean of its divisors is an integer number (332202769).

Almost surely, 2^664405537 is an apocalyptic number.

It is an amenable number.

664405537 is a deficient number, since it is larger than the sum of its proper divisors (1).

664405537 is an equidigital number, since it uses as much as digits as its factorization.

664405537 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 302400, while the sum is 40.

The square root of 664405537 is about 25776.0651962242. The cubic root of 664405537 is about 872.5917066847.

The spelling of 664405537 in words is "six hundred sixty-four million, four hundred five thousand, five hundred thirty-seven".