644022311 has 2 divisors, whose sum is σ = 644022312. Its totient is φ = 644022310.

The previous prime is 644022293. The next prime is 644022329. The reversal of 644022311 is 113220446.

It is a balanced prime because it is at equal distance from previous prime (644022293) and next prime (644022329).

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-644022311 is a prime.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (644022361) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322011155 + 322011156.

It is an arithmetic number, because the mean of its divisors is an integer number (322011156).

Almost surely, 2^644022311 is an apocalyptic number.

644022311 is a deficient number, since it is larger than the sum of its proper divisors (1).

644022311 is an equidigital number, since it uses as much as digits as its factorization.

644022311 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1152, while the sum is 23.

The square root of 644022311 is about 25377.5946653736. The cubic root of 644022311 is about 863.5754833072.

Adding to 644022311 its reverse (113220446), we get a palindrome (757242757).

The spelling of 644022311 in words is "six hundred forty-four million, twenty-two thousand, three hundred eleven".