644311267 has 2 divisors, whose sum is σ = 644311268. Its totient is φ = 644311266.

The previous prime is 644311253. The next prime is 644311273. The reversal of 644311267 is 762113446.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 644311267 - 2²³ = 635922659 is a prime.

It is not a weakly prime, because it can be changed into another prime (644311207) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322155633 + 322155634.

It is an arithmetic number, because the mean of its divisors is an integer number (322155634).

Almost surely, 2^644311267 is an apocalyptic number.

644311267 is a deficient number, since it is larger than the sum of its proper divisors (1).

644311267 is an equidigital number, since it uses as much as digits as its factorization.

644311267 is an evil number, because the sum of its binary digits is even.

The product of its digits is 24192, while the sum is 34.

The square root of 644311267 is about 25383.2871590738. The cubic root of 644311267 is about 863.7046185884.

The spelling of 644311267 in words is "six hundred forty-four million, three hundred eleven thousand, two hundred sixty-seven".