844497199821 has 12 divisors (see below), whose sum is σ = 1237665318176. Its totient is φ = 511816484520.

The previous prime is 844497199801. The next prime is 844497199829. The reversal of 844497199821 is 128991794448.

It is not a de Polignac number, because 844497199821 - 2¹¹ = 844497197773 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (844497199829) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1163218921 + ... + 1163219646.

Almost surely, 2^844497199821 is an apocalyptic number.

It is an amenable number.

844497199821 is a deficient number, since it is larger than the sum of its proper divisors (393168118355).

844497199821 is a wasteful number, since it uses less digits than its factorization.

844497199821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2326438592 (or 2326438581 counting only the distinct ones).

The product of its digits is 41803776, while the sum is 66.

The spelling of 844497199821 in words is "eight hundred forty-four billion, four hundred ninety-seven million, one hundred ninety-nine thousand, eight hundred twenty-one".