644424212051 has 2 divisors, whose sum is σ = 644424212052. Its totient is φ = 644424212050.

The previous prime is 644424211943. The next prime is 644424212057. The reversal of 644424212051 is 150212424446.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 644424212051 - 2³⁰ = 643350470227 is a prime.

It is not a weakly prime, because it can be changed into another prime (644424212057) 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, 322212106025 + 322212106026.

It is an arithmetic number, because the mean of its divisors is an integer number (322212106026).

Almost surely, 2^644424212051 is an apocalyptic number.

644424212051 is a deficient number, since it is larger than the sum of its proper divisors (1).

644424212051 is an equidigital number, since it uses as much as digits as its factorization.

644424212051 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 61440, while the sum is 35.

Adding to 644424212051 its reverse (150212424446), we get a palindrome (794636636497).

The spelling of 644424212051 in words is "six hundred forty-four billion, four hundred twenty-four million, two hundred twelve thousand, fifty-one".