1644827819899 has 4 divisors (see below), whose sum is σ = 1794357621720. Its totient is φ = 1495298018080.

The previous prime is 1644827819893. The next prime is 1644827819903. The reversal of 1644827819899 is 9989187284461.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1644827819899 - 2¹⁵ = 1644827787131 is a prime.

It is a super-2 number, since 2×1644827819899² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1644827819893) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 74764900894 + ... + 74764900915.

It is an arithmetic number, because the mean of its divisors is an integer number (448589405430).

Almost surely, 2^{1644827819899} is an apocalyptic number.

1644827819899 is a deficient number, since it is larger than the sum of its proper divisors (149529801821).

1644827819899 is a wasteful number, since it uses less digits than its factorization.

1644827819899 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 149529801820.

The product of its digits is 501645312, while the sum is 76.

The spelling of 1644827819899 in words is "one trillion, six hundred forty-four billion, eight hundred twenty-seven million, eight hundred nineteen thousand, eight hundred ninety-nine".