21785944451428 has 12 divisors (see below), whose sum is σ = 38187597578620. Its totient is φ = 10875202286112.

The previous prime is 21785944451351. The next prime is 21785944451449. The reversal of 21785944451428 is 82415444958712.

It can be written as a sum of positive squares in 2 ways, for example, as 141472272384 + 21644472179044 = 376128^2 + 4652362^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21785944451428.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4442482143 + ... + 4442487046.

Almost surely, 2^{21785944451428} is an apocalyptic number.

It is an amenable number.

21785944451428 is a deficient number, since it is larger than the sum of its proper divisors (16401653127192).

21785944451428 is a wasteful number, since it uses less digits than its factorization.

21785944451428 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8884969806 (or 8884969804 counting only the distinct ones).

The product of its digits is 103219200, while the sum is 64.

The spelling of 21785944451428 in words is "twenty-one trillion, seven hundred eighty-five billion, nine hundred forty-four million, four hundred fifty-one thousand, four hundred twenty-eight".