21055542105 has 48 divisors (see below), whose sum is σ = 36906851520. Its totient is φ = 10189785216.

The previous prime is 21055542097. The next prime is 21055542107. The reversal of 21055542105 is 50124555012.

It is not a de Polignac number, because 21055542105 - 2³ = 21055542097 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21055542107) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 663286 + ... + 694304.

It is an arithmetic number, because the mean of its divisors is an integer number (768892740).

Almost surely, 2^21055542105 is an apocalyptic number.

It is an amenable number.

21055542105 is a deficient number, since it is larger than the sum of its proper divisors (15851309415).

21055542105 is a wasteful number, since it uses less digits than its factorization.

21055542105 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31158 (or 31099 counting only the distinct ones).

The product of its (nonzero) digits is 10000, while the sum is 30.

The spelling of 21055542105 in words is "twenty-one billion, fifty-five million, five hundred forty-two thousand, one hundred five".