644806307 has 2 divisors, whose sum is σ = 644806308. Its totient is φ = 644806306.

The previous prime is 644806247. The next prime is 644806319. The reversal of 644806307 is 703608446.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 644806307 - 2¹⁰ = 644805283 is a prime.

It is a super-3 number, since 3×644806307³ (a number of 27 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (644806907) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322403153 + 322403154.

It is an arithmetic number, because the mean of its divisors is an integer number (322403154).

Almost surely, 2^644806307 is an apocalyptic number.

644806307 is a deficient number, since it is larger than the sum of its proper divisors (1).

644806307 is an equidigital number, since it uses as much as digits as its factorization.

644806307 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 96768, while the sum is 38.

The square root of 644806307 is about 25393.0365848592. The cubic root of 644806307 is about 863.9257637084.

The spelling of 644806307 in words is "six hundred forty-four million, eight hundred six thousand, three hundred seven".