644552220149 has 2 divisors, whose sum is σ = 644552220150. Its totient is φ = 644552220148.

The previous prime is 644552220113. The next prime is 644552220173. The reversal of 644552220149 is 941022255446.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 555312607249 + 89239612900 = 745193^2 + 298730^2 .

It is a cyclic number.

It is not a de Polignac number, because 644552220149 - 2³² = 640257252853 is a prime.

It is a super-3 number, since 3×644552220149³ (a number of 36 digits) contains 333 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (644552220199) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322276110074 + 322276110075.

It is an arithmetic number, because the mean of its divisors is an integer number (322276110075).

Almost surely, 2^644552220149 is an apocalyptic number.

It is an amenable number.

644552220149 is a deficient number, since it is larger than the sum of its proper divisors (1).

644552220149 is an equidigital number, since it uses as much as digits as its factorization.

644552220149 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 691200, while the sum is 44.

The spelling of 644552220149 in words is "six hundred forty-four billion, five hundred fifty-two million, two hundred twenty thousand, one hundred forty-nine".