644266699 has 2 divisors, whose sum is σ = 644266700. Its totient is φ = 644266698.

The previous prime is 644266643. The next prime is 644266739. The reversal of 644266699 is 996662446.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 644266699 - 2¹¹ = 644264651 is a prime.

It is not a weakly prime, because it can be changed into another prime (644266619) 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, 322133349 + 322133350.

It is an arithmetic number, because the mean of its divisors is an integer number (322133350).

Almost surely, 2^644266699 is an apocalyptic number.

644266699 is a deficient number, since it is larger than the sum of its proper divisors (1).

644266699 is an equidigital number, since it uses as much as digits as its factorization.

644266699 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3359232, while the sum is 52.

The square root of 644266699 is about 25382.4092434111. The cubic root of 644266699 is about 863.6847035375.

The spelling of 644266699 in words is "six hundred forty-four million, two hundred sixty-six thousand, six hundred ninety-nine".