21555207105 has 16 divisors (see below), whose sum is σ = 35420449344. Its totient is φ = 11185404480.

The previous prime is 21555207083. The next prime is 21555207109. The reversal of 21555207105 is 50170255512.

It is not a de Polignac number, because 21555207105 - 2⁵ = 21555207073 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21555207109) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 19418551 + ... + 19419660.

It is an arithmetic number, because the mean of its divisors is an integer number (2213778084).

Almost surely, 2^21555207105 is an apocalyptic number.

It is an amenable number.

21555207105 is a deficient number, since it is larger than the sum of its proper divisors (13865242239).

21555207105 is a wasteful number, since it uses less digits than its factorization.

21555207105 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38838256.

The product of its (nonzero) digits is 17500, while the sum is 33.

The spelling of 21555207105 in words is "twenty-one billion, five hundred fifty-five million, two hundred seven thousand, one hundred five".