664623361 has 2 divisors, whose sum is σ = 664623362. Its totient is φ = 664623360.

The previous prime is 664623359. The next prime is 664623367. The reversal of 664623361 is 163326466.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 432640000 + 231983361 = 20800^2 + 15231^2 .

It is a cyclic number.

It is not a de Polignac number, because 664623361 - 2¹ = 664623359 is a prime.

Together with 664623359, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 664623361.

It is not a weakly prime, because it can be changed into another prime (664623367) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332311680 + 332311681.

It is an arithmetic number, because the mean of its divisors is an integer number (332311681).

Almost surely, 2^664623361 is an apocalyptic number.

It is an amenable number.

664623361 is a deficient number, since it is larger than the sum of its proper divisors (1).

664623361 is an equidigital number, since it uses as much as digits as its factorization.

664623361 is an evil number, because the sum of its binary digits is even.

The product of its digits is 93312, while the sum is 37.

The square root of 664623361 is about 25780.2901651630. The cubic root of 664623361 is about 872.6870554025.

The spelling of 664623361 in words is "six hundred sixty-four million, six hundred twenty-three thousand, three hundred sixty-one".