21505502006705 has 8 divisors (see below), whose sum is σ = 26504078149032. Its totient is φ = 16739417778048.

The previous prime is 21505502006693. The next prime is 21505502006789. The reversal of 21505502006705 is 50760020550512.

21505502006705 is digitally balanced in base 6, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 3183412460944 + 18322089545761 = 1784212^2 + 4280431^2 .

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

It is not a de Polignac number, because 21505502006705 - 2⁸ = 21505502006449 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 58122978212 + ... + 58122978581.

It is an arithmetic number, because the mean of its divisors is an integer number (3313009768629).

Almost surely, 2^{21505502006705} is an apocalyptic number.

It is an amenable number.

21505502006705 is a deficient number, since it is larger than the sum of its proper divisors (4998576142327).

21505502006705 is a wasteful number, since it uses less digits than its factorization.

21505502006705 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 116245956835.

The product of its (nonzero) digits is 105000, while the sum is 38.

The spelling of 21505502006705 in words is "twenty-one trillion, five hundred five billion, five hundred two million, six thousand, seven hundred five".