21831839685 has 20 divisors (see below), whose sum is σ = 39135594828. Its totient is φ = 11643647616.

The previous prime is 21831839593. The next prime is 21831839737. The reversal of 21831839685 is 58693813812.

21831839685 is a `hidden beast` number, since 218 + 31 + 8 + 396 + 8 + 5 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 12539072484 + 9292767201 = 111978^2 + 96399^2 .

It is not a de Polignac number, because 21831839685 - 2⁸ = 21831839429 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 26952484 + ... + 26953293.

Almost surely, 2^21831839685 is an apocalyptic number.

It is an amenable number.

21831839685 is a deficient number, since it is larger than the sum of its proper divisors (17303755143).

21831839685 is an equidigital number, since it uses as much as digits as its factorization.

21831839685 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53905794 (or 53905785 counting only the distinct ones).

The product of its digits is 2488320, while the sum is 54.

The spelling of 21831839685 in words is "twenty-one billion, eight hundred thirty-one million, eight hundred thirty-nine thousand, six hundred eighty-five".