644834211338 has 32 divisors (see below), whose sum is σ = 1037198260800. Its totient is φ = 299769997824.

The previous prime is 644834211337. The next prime is 644834211347. The reversal of 644834211338 is 833112438446.

It is a super-2 number, since 2×644834211338² (a number of 24 digits) contains 22 as substring.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 644834211292 and 644834211301.

It is not an unprimeable number, because it can be changed into a prime (644834211337) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 214106 + ... + 1155642.

It is an arithmetic number, because the mean of its divisors is an integer number (32412445650).

Almost surely, 2^644834211338 is an apocalyptic number.

644834211338 is a deficient number, since it is larger than the sum of its proper divisors (392364049462).

644834211338 is a wasteful number, since it uses less digits than its factorization.

644834211338 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 941894.

The product of its digits is 1327104, while the sum is 47.

The spelling of 644834211338 in words is "six hundred forty-four billion, eight hundred thirty-four million, two hundred eleven thousand, three hundred thirty-eight".