644552220199 has 2 divisors, whose sum is σ = 644552220200. Its totient is φ = 644552220198.

The previous prime is 644552220181. The next prime is 644552220209. The reversal of 644552220199 is 991022255446.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 644552220199 - 2⁷ = 644552220071 is a prime.

It is a super-3 number, since 3×644552220199³ (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 (644552220149) 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, 322276110099 + 322276110100.

It is an arithmetic number, because the mean of its divisors is an integer number (322276110100).

Almost surely, 2^644552220199 is an apocalyptic number.

644552220199 is a deficient number, since it is larger than the sum of its proper divisors (1).

644552220199 is an equidigital number, since it uses as much as digits as its factorization.

644552220199 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1555200, while the sum is 49.

The spelling of 644552220199 in words is "six hundred forty-four billion, five hundred fifty-two million, two hundred twenty thousand, one hundred ninety-nine".