1644012216 has 192 divisors, whose sum is σ = 5793016320. Its totient is φ = 408418560.

The previous prime is 1644012203. The next prime is 1644012263. The reversal of 1644012216 is 6122104461.

1644012216 is a `hidden beast` number, since 1 + 6 + 440 + 1 + 2 + 216 = 666.

It is a super-3 number, since 3×1644012216³ (a number of 29 digits) contains 333 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 1644012216.

It is a congruent number.

It is an unprimeable number.

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 47 ways as a sum of consecutive naturals, for example, 121066 + ... + 133958.

It is an arithmetic number, because the mean of its divisors is an integer number (30171960).

Almost surely, 2^1644012216 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1644012216, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2896508160).

1644012216 is an abundant number, since it is smaller than the sum of its proper divisors (4149004104).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1644012216 is a wasteful number, since it uses less digits than its factorization.

1644012216 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12946 (or 12939 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 27.

The square root of 1644012216 is about 40546.4205078574. The cubic root of 1644012216 is about 1180.2346119735.

Adding to 1644012216 its reverse (6122104461), we get a palindrome (7766116677).

The spelling of 1644012216 in words is "one billion, six hundred forty-four million, twelve thousand, two hundred sixteen".