664636837 has 2 divisors, whose sum is σ = 664636838. Its totient is φ = 664636836.

The previous prime is 664636799. The next prime is 664636897. The reversal of 664636837 is 738636466.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 659411041 + 5225796 = 25679^2 + 2286^2 .

It is a cyclic number.

It is not a de Polignac number, because 664636837 - 2¹⁹ = 664112549 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (664636897) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332318418 + 332318419.

It is an arithmetic number, because the mean of its divisors is an integer number (332318419).

Almost surely, 2^664636837 is an apocalyptic number.

It is an amenable number.

664636837 is a deficient number, since it is larger than the sum of its proper divisors (1).

664636837 is an equidigital number, since it uses as much as digits as its factorization.

664636837 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2612736, while the sum is 49.

The square root of 664636837 is about 25780.5515262959. The cubic root of 664636837 is about 872.6929536059.

The spelling of 664636837 in words is "six hundred sixty-four million, six hundred thirty-six thousand, eight hundred thirty-seven".