644374942249 has 2 divisors, whose sum is σ = 644374942250. Its totient is φ = 644374942248.

The previous prime is 644374942213. The next prime is 644374942271. The reversal of 644374942249 is 942249473446.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 407139705625 + 237235236624 = 638075^2 + 487068^2 .

It is a cyclic number.

It is not a de Polignac number, because 644374942249 - 2¹⁵ = 644374909481 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 644374942193 and 644374942202.

It is not a weakly prime, because it can be changed into another prime (644374942279) 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, 322187471124 + 322187471125.

It is an arithmetic number, because the mean of its divisors is an integer number (322187471125).

Almost surely, 2^644374942249 is an apocalyptic number.

It is an amenable number.

644374942249 is a deficient number, since it is larger than the sum of its proper divisors (1).

644374942249 is an equidigital number, since it uses as much as digits as its factorization.

644374942249 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 41803776, while the sum is 58.

The spelling of 644374942249 in words is "six hundred forty-four billion, three hundred seventy-four million, nine hundred forty-two thousand, two hundred forty-nine".