21108547693 has 8 divisors (see below), whose sum is σ = 21681202328. Its totient is φ = 20536006464.

The previous prime is 21108547687. The next prime is 21108547711. The reversal of 21108547693 is 39674580112.

It is the 59314-th star number.

It can be written as a sum of positive squares in 4 ways, for example, as 4843881604 + 16264666089 = 69598^2 + 127533^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21108547693 - 2³³ = 12518613101 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21108547673) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 462655 + ... + 506227.

It is an arithmetic number, because the mean of its divisors is an integer number (2710150291).

It is a 2-persistent number, because it is pandigital, and so is 2⋅21108547693 = 42217095386, but 3⋅21108547693 = 63325643079 is not.

Almost surely, 2^21108547693 is an apocalyptic number.

It is an amenable number.

21108547693 is a deficient number, since it is larger than the sum of its proper divisors (572654635).

21108547693 is a wasteful number, since it uses less digits than its factorization.

21108547693 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56703.

The product of its (nonzero) digits is 362880, while the sum is 46.

The spelling of 21108547693 in words is "twenty-one billion, one hundred eight million, five hundred forty-seven thousand, six hundred ninety-three".