644235167 has 2 divisors, whose sum is σ = 644235168. Its totient is φ = 644235166.

The previous prime is 644235161. The next prime is 644235199. The reversal of 644235167 is 761532446.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 644235167 - 2²⁰ = 643186591 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 644235167.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (644235161) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322117583 + 322117584.

It is an arithmetic number, because the mean of its divisors is an integer number (322117584).

Almost surely, 2^644235167 is an apocalyptic number.

644235167 is a deficient number, since it is larger than the sum of its proper divisors (1).

644235167 is an equidigital number, since it uses as much as digits as its factorization.

644235167 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 120960, while the sum is 38.

The square root of 644235167 is about 25381.7880969801. The cubic root of 644235167 is about 863.6706130217.

The spelling of 644235167 in words is "six hundred forty-four million, two hundred thirty-five thousand, one hundred sixty-seven".